Costs mount up very quickly, especially with film. Film is good though and many people, especially older folks will love the fact you're sticking with something they know.
At 14, you will have real difficulty making money, not the least of which is the tax situation - which you really don't want to get into. Keep things casual and cash and don't try to make lots of money, but also be fair to yourself - charge the costs + 20%. Tell people that is how it is and they'll respect it.
Events photography is difficult. There is also a large chance of stiff competition from someone who is closer friends with the organiser/family etc.
My advice would be to practise taking pictures at your own expense, and get the great ones printed out a little larger than standard size, and try and sell some prints. Start small - beg for a stall at a car boot sale or similar and try and sell a couple of pictures. You'll quickly learn what sells - play the sympathy card - you're a young artist trying to make a break...
Also, for exposure, use a website as a gallery there a plenty out there who offer a range of free services, don't pay for anything to start with. My site
www.ukphotographs.com gives people galleries for free (if they are of a certain standard). With exposure and getting known, you can get business cards, but this will look a bit funny from a 14yo and you must be careful who you give them to. Take a friend round with you, or preferably a parent whenever you're attempting something new.
Start with charity events, village fetes, markets. The local church will be a massive photographic and marketing opportunity - talk to the vicar/preacher/rabbi or whomever FIRST and get them on side. They might even let you do a talk to the congregation if you can do a photographic competition for everyone like "Easter Pictures".
Ideas should come easily to you, and don't let anyone tell you that something won't work - find out for yourself (without spending too many $$$).
Good luck.