Crib + blanket?

My son is 3 1/2 months old and we are going to start to try putting him in his crib now to sleep, but my son loves his blankets, so I want to put one with him when he sleeps, but I'm kinda worried about him trying to snuggle with the blanket too much, what do you mommies think? When did you allow blankets with your little one? I have another son, but he's 5, and I don't remember when I allowed blankets with him. Hahaha