Baby sleeping bags/gro bags...advice please?!

M & C’s Mummy 💙💜

I am trying My son in a 2.5tog sleeping bag tonight coz he has decided to start trying to pull his blanket over his face. it's not a gro bag just one from Asda.

On our gro egg thermometer our room is usually between 20c and 21c so I put him in a long sleeve vest and the sleeping bag. Is that right or will he be too warm? I am so worried about over heating him