Is My Hairline Maturing Over a 2 Year Period?

Hi, i realise that this is a similar question to others you have been asked but i would really appreciate it if you could lend me your knowledge.

Basically i have blonde hair, at the temples it has always been really bright, white hair, the rest went brown and at 18 the bright blonde started to thin. i am now 20 and in the space of a
year and a half the temple areas have receded and changed to around a 2 on the Norwood scale.

Is it normal for a maturing hairline transition to happen this quickly?

Yes, it is possible. Maturation of the hairline can start at around 16 years old and can progress with different speeds in different individuals. Some patients complete their maturation in one to two years, while in some the process may take up to several years and could be mistaken for progression of male patterned baldness.