The clitoris is much more exposed outside than it is inside the vagina. For most women penetration doesn't feel that much compared external forms of stimulations.

Just look for someone that's not judgmental and that you can talk to about sexcbefor doing it and explain. A ton of women complain that sex revolves too much around penetration for them. Odds are they won't have any issue with you not being interested in it and they might even see this as a plus.