15-Year-Old Seeking Tips to Prevent Hair Loss; Norwood Level 2?

Im trying to find out what level is this and if Im still able to save it.

Do u have any tips abt what should I use to prevent it? (Im 15)

I also want to have long hair atleast once in my life so if anyone have any tips for that too then pls type them down here.

I alr went to a trichologist that gave me shampoos i should use and she told me Im level 2.(Im not sure abt that)