Hey Maanav:)

Thanks for reaching out!

Yes,you can start attending classes in your round 1 college if you don't want to waste time, but remember your admission there is provisional if you opted for upgradation. If you later get a new seat in round 2,your round 1 seat will be cancelled and you'll have to shift. The fee you paid in round 1 will be adjusted when you join the upgraded college, though a small part maybe reduced depending on Institute's rules.This is why many students wait until round 2 is out.But if you prefer not to lose time you can join the classes,just be ready to move if upgradation happens.

Hope this helps!