How to get a guys number in middle school?

Okay so this guy i really like him. I had 1 cl with him last year (6th grade) and this year i have 1 again. He only really knows my first and last name because my friend introduced me to his friends. Well in gym i wanted to get his number, but I'm really shy around guys. So I wanted to know if complimenting him on something (like his shoes) and then start a conversation and before the period ends ask for his number. Do you think this is a good idea? Or do you think it won't work? I wanna know really soon because i was gonna try this tomorrow (when i have gym with him) and i also wanna be his friend(like one of his best friends) so for my birthday i could invite him without it being really weird. My birthday is in 4 months and in 2 months he switches from gym to health so i won't have any cles with him except for lunch. Yes i could sit at his table for lunch because im friends with everyone at his table. :) Thanks love yaaa <333