at what age does a boy become a young friend ??

is it usually :

9-10 yrs old ?

11-12 yrs old ?

12+ years old ?

and how long usually would the relationship last for ?

The reason i ask is because i have just me and become friends with a 9year old boy ... is this unusually young ?

this is my first time my thoughts are only with boys rather than girls
habe you any advice for me to think about to make this last ?

have a great day :)

TO_Guy