I'm so sorry for your troubles! I have 21 and 18 year old daughters. You'll just have to tuck all this advice away to consider, because advice is hard to follow when you're in the middle of the problem. While many high school romances survive, you are very young.
I've told my girls that dating is like shopping. You don't really know your wish list until you've tried some things on. For example (although maybe oversimplified), you might think you want someone that sends you flowers. But if you had someone that sent you flowers but didn't listen when you talked about your day, you'd discover that flowers aren't really all that important and change your wish list.
Also, everyone matures at a different rate. And you might just be maturing a little faster than your bf. He may catch up, but it might be a couple years down the road. So tread lightly and beware of commitment until then.
And about the car thing - I'm married to a performance car guy. While I do often "lose" him to the garage - I ALWAYS know where he is. Some wives would trade a "beer-with-the-buddies" guy for a "car guy" in a minute.
Hugs.