Start to prep

Welcome
Don't stress about your age
I like many others started prepping as a teenager,or survivalism as it was called back then
A lifetime of projects awaits you!
learn as many Prepper related skills as you can
And collect gear as the budget allows and improves
Never keep your eye off the prepping ball!

Heya Jap, firstly join the forum proper, instead of just being a guest  

I was a scout as a young teenager, we learned a lot about making fires, tying knots, building structures, hiking, camping, which teach you how to get by on less, I did a leadership course, first aid, cooking, survival camp and we even did a nuclear/post nuclear camp. Luckily we had active leaders who loved to camp and hike so we had an activity every second [and sometimes every] weekend. I don't know your current age, nor what scouting is like these days, though there were a TON of information I still hold as useful in those couple of years, 28 years later.  The scout motto, 'be prepared' is a very old one.  There's also groups for older teenagers and young adults.  It's free to check out, might be worth a look.  

As already stated a lot of knowledge is available on the 'nets', perhaps a bit daunting on where to start. To this I would suggest focus on what prepping is about, surviving situations, disasters and difficulties.  What?  I'll get to that, the reality of these events is that small events impact people in your life are occasional and likely eventually, such as having a spare tyre is prepping and being able to change it is being prepared if you do have a flat. Of course major events as TV shows focus on are probably never going to happen, prepping is about making sure you've got options in the minor events and the major events. So, with knowledge, you have options.

For survival humans it's been said that we have 3 mins to find air, 3 hours to have shelter, 3 days for water and 3 weeks for food.  So we want to remember those areas of focus.  When I was in scouts we learned that even a day hike we carry some water and something like a space blanket [for shelter] as well as suitable clothing, a pocket knife and some trail mix [dried fruit and nuts].  We went with more than ourselves and we told someone who's not going where we were, the path we were going and when we would be home.  This is so people could find us if we had a problem.  These days, we'd have a phone and probably a spare battery.  With the space blanket we have shelter and warmth.  Similar principles apply, we prep to have options.   

Water
In a cyclone, the typical cry is to fill the bathtub for good reason, we need water!  Sure you can spend $4 and get a 10L aldi water container, or fill well cleaned [detergent] old soft drink containers filled with tap water [which works just fine] for free and it's worth looking and thinking about other sources too.  Is there a lake, pond or pool nearby?  How do we make the water safe to drink?  These are things we would want to undestand and that costs nothing. 
 
Did you know that many hot water units hold 250L of water? Did you know we need about 4L/day, some for drinking and some for a little cleaning. So maths is useful in that a typical hot water service holds 2 months water for 1 person and is almost always full.  Some hot water services are larger and some are instant hot water and store no water. 

Food
Did you know that those soft drink containers have a silicone seal on top and make great long term storage containers for things like rice and beans if you keep them out of sunlight?  Prepping, at least to my mind, is about independence, so using mums rice might be a free start, but it's not the same as you doing a paper round/mowing etc and earning a few dollars to spend on some rice.  Learning independence is an important part to prepping and when you're paying for it yourself you will spend a LOT more time being careful to what you spend it on, you'll look for the special prices [.10-.12c/100g is decent].  Rice in those clean drink containers is a pretty good deal to start with.  Some other thoughts might be, do you know how much energy humans need?  How much rice would you need in a day?  It's not very much actually as you'll discover.  Whilst energy [Kilojoules] is important, what else do we need?  Eventually after doing some research, you'll figure out how little you need for a weeks worth of food and you might save up and eventually buy a week to begin with.  The rice and be__s is about as cheap as you can start.  Do you know how to cook them?  Can you cook them without power/gas?  Well you can sprout most be__s [not all!! do research as to those you cant.] and soak rice and whilst not too fun to eat [try it and find out] it would keep you going.  Sure you could collect cans of food of what you 'normally' eat, but the costing is far more. 

Prepping is not just about collecting stuff, it's also about renewing what you need for survival.  So when it comes to food, how do we grow it?  Seed is 'very' cheap and you can get it from the supermarket, or even collect them from vegetables [tomatoes for instance] or grow some potatoes or carrot from a piece cut off.  I've currently got some garlic that self sprouted in my kitchen window that I'll put in the garden in a couple of days.  Learning how to grow a small veggie patch is a GREAT prepping task and you can learn a lot about soil quality, responsibility [watering!], patience and a respect for where food comes from etc.   

Mostly, have fun and remember the chances of SHTF are extremely small in your lifetime, so work on having a good life whilst you're at it.  How do you prep for a good life?  Prepping is 'insurance', like that spare tyre, a part of your life, not 'your life', a balance of things is a good plan for life.

Hi, Jap! Welcome the the forum.

I would say there are two things you can do, that no parent would ever object to!

1) Plant a garden
2) Start developing some useful skills: Things like knowing how to sew, how to weld, how to do woodwork, plumbing, electrical, etc... The list is pretty much endless!

Good luck.