Thinning hair on crown

[Anotherworriedteenager]

Hello!
I created this Account because I noticed that my Hair start to thin out...
I am 18 years old.
My dad is 55 and he has NW 4,5
My Mother's side Grandfather is 85 and he has NW 2 (or maybe even 1)
I have NW 2

I started Weightlifting around a year ago (Around June).
In December I noticed that I have thin hair on my sides.

Weightlifting does increase Testosterone levels. Does that mean that I have a higher DHT level too?

I don't want to stop Lifting but I also want to keep my hair for as long as possible.
I read that Finasterid costs about 50€ per Month and as a student i cannot afford that.

(Sorry if I have bad english)
Attachment: Photo of my crown