Welcome to BP. I wish i would have heard of this place when i was 18, im 26 now and wished i had tried to save more of what ive made through my work life, so you're already ahead of the game. Just think of the money you can make by doing comps on a friday night instead of going to walmart at 3am to goof around in the toy section like others do in our age group when they are bored? Defiantly dont let your age stop you! Good luck and see you around the forum.
Building up your credit is easy. First try to find a credit card about 300 dollars with no annual fee. Remember that credit cards report to credit bureau around the 1st and the 12-15th of the month. If you spend over 50% of the cards value, you get derogatory remarks on your report and your numbers fall, while paying the balance down below that value will make your score go up. So try not to max your cards out, and if you do, make sure you have enough cash to cover 55 or 60% of it. As a personal preference i like to pay on mine weekly. Ive had a good score, had time to mess it up with a medical bill and have almost rebounded. Its a game you've got to stay ontop of for sure but building up your score isnt hard. They just want to see repetitive payments