My son is 97days and is trying to sit and has itchy gums. is it possible that he is teething?

It's possible: There's a very wide range on when an infant starts teething, all perfectly normal. There are some babies that are born with teeth!

Teething: A little early, but not unusual. Teething is a process as opposed to a singular event. Teeth erupt slowly, taking time to exit the supporting gums/bone. It may actually be weeks to months until the teeth actually emerge. Standard of Care is that all children see a Dentist at emergence of 1st tooth but not later than 1st b'day. Recommend that you see a children's dental specialist, a Pedodontist.