When Will My Infant Start Playing With Toys?

I was wondering when will my baby Jadah start sitting up on her own and playing with her toys? She is 3 months old and Ive tried to introduce rattles to her and little bears. Also could she be teething ?…
She always has her hands in her mouth and slobbing She also like to chew on her clothes to where the front of her shirt in soaking wet.
thanx everyone!