Most first time moms feel their baby moving around 20 weeks gestation.
Women who have had children
can sometimes feel the baby a couple weeks earlier. However, 3 months would be a bit early, and you might simply be feeling your intestines digesting food. I concur - assuming your dates are good 3 months (12 weeks) is early - probably something else and not the baby.
Answer assisted by Marianne Di Napoli, Medical Student