Several questions regarding finasteride

[Jackito]

I'm a 19 year old with a mature hairline who is considering taking finasteride as a precautionary measure. My hairline has moved up a bit over the past year, forming a wide v shape.

The reason I'm considering finasteride is that I'm currently sitting in a life or death situation here. My father has a thick mature hairline at 45, my maternal granddad is essentially the same and I don't think they developed their mature hairlines until mid 20's.

There's one side in which balding is present in my family and that's my maternal grandmother's of whom my crown sits in the exact same place as her's. My nan's brother is a Norwood 7 but I'm not sure what age he got to that stage.

Anyway.. if I was to take finasteride now, would it effect me/the development of my body as I'm still only 19 and likely still within the process of puberty.

Say for example I start taking finasteride for 5 years now. After that 5 years.. could withdrawing finasteride aggravate the MPB as my body would've adjusted to the lower levels of DHT for them to rise again.

Is there any cases where males have used finasteride for over 15 years? I seriously can't let myself go bald, it would be the end of me so when the balding does come for me I intend to combat it for as long as I possibly can

[Simar]

But its risky to take Finasteride at such a younger age. IT Can affect your body adversally.