Hey, sorry to hear you're going through this. I know it's tough, especially getting this at such a young age. To be honest, I'm not sure there's a permanent solution since this is an extremely rare condition. That is why there is barely any scientific research or knowledge on exfoliative cheilitis, and it is also why dermatologists or medicine barely help since this condition is largely unknown. However, if you read through the forum, some people claim to be cured through steroids, probiotics etc.
As for myself, I don't have the time or money to spend on dermatologists (since they don't know what to do anyway) so I just manage this by manually peeling every other day. People say it's bad but t's better that going out with with nasty yellow crusty lips. There is no guarantee that leaving them alone will cure them. Besides, I think my lips look normal when I peel. At least this way I can live a little.
If it's any consolation, I'm 21 years old as well and my EC began when I was 16-17, just like you, so just know that you're not alone. If you need some advice or someone to talk to, you can always shoot me a PM