Entered late egg stage at 15 I kinda knew then, I repressed from 17 to 18+1/2, after that I started exploring my gender again (stuff like shaving leg, epilating, etc...) and eventually realised I wasn't living for myself but for others when I was 19 (2-3 months away from turning 20) and decided then and there that I would transition, I came out to my parents a month after and tried to get HRT immediately, at the same time I changed my pronouns and my name with them as well, it took me nearly five months to be able to start the treatment (had to store my sperm). I was 20 and now I'm 7months on HRT :)
I understand not feeling valid enough for HRT the best way I can put it is: put aside the validity of your trans identity, do you want all the effects of HRT despite the "downsides"? you don't have to be trans to get HRT.