My 3-year old son prefers to wear crocs or native only almost all the time. I'm having a hard time convincing him to wear closed shoes especially when we need to attend a semi formal or formal event. Is this normal? Lol

It's definitely normal! Kids grow into routines and those shoes are part of his routine. Nothing to worry about, but it'd probably be wise to coax him into wearing other shoes from time to time since he'll eventually grow out of those!