S.H.
No its not weird. ALL the moms I know, my friends, have had similar things happen, in this age kids.
My son, likes my armpits! I asked him why and he said its "cozy" and he likes the smell and that it is pokey. ie: hair stubble. It is comforting to him.
My other friends said, their kids liked to hang onto their hair too... falling asleep or otherwise. Or, some of their kids like a certain area on their neck to smell and touch.
The point being, it is comforting to them and the smell of "Mom" is nice for them. It is a kind of bonding. Even my Mom herself, said when she was that age, she liked her Mom's smell and liked to cuddle up to her neck and rub her ears.
Anyway, no its not abnormal. Nor weird.
All the best,
Susan