Harsh but true!
For what it's worth my first bit of advise is to ignore those who even hint or suggest that you should be quitting! If it is what you really, really, want to do, and you have the determination to keep going until you achieve your goal, the thought of quitting should never cross your mind.
To some in this profession jobs were gifted, many struggled to jump the hoops, and many others faced a walk through treacle before eventually realising their dream. Sure, right now for most it is harder to get a foot onto the bottom rung, and there is a lot of competition out there. That may seem discouraging but one thing you do have, that thousands do not, is a medical certificate, and that makes you a VERY lucky boy!
I know one guy with a birth defect who was told he would NEVER get a medical, and another one with learning difficulties who was advised to stop dreaming of becoming a pilot! It took them both a very long swim through sh1t and tar, but as a result of perseverance, doggedness and damned hard work, without complaining I should add, they are both now flying shiny new jets. It took them a little while mind, 17 years and 19 years respectively, but hey, you're only a kid, so get up your fit young arse and do what thousands before you have done. Get stuck in, suffer the short term consequences and deal with achieving goals, one step at a time. If you want it enough it will happen. I promise!