Martin,
Good news is you are 21! More good news is that your hairloss has been slowed down with the use of rogaine and propecia right? Also you can pull off using concealers still. You are still young enough where in hopefully "fingers crossed" just a short period of time they will have a cure for MPB. Just hang on for a little longer because they are aggressivly working on finding cures. I am also a diffuse thinner that started losing my hair at 21. I did nothing about it until I was 28. By that time I had lost quite a bit, but in the 2 years that I've been uing rogaine and minox my hairloss has been stabilized. Good luck