Many people will suggest a 20g for a female shooter. While the suggestion dos have some merit, even a little person can be very comfortable shooting a 12g if it fits properly and he or she is shooting it properly. So, don't rule out a 12g. Hell, I've met a few women shooters who shoot 500-1000 rounds of 12g almost EVERY DAY and have since they were 10-12 years old. Perceived recoil has more to do with fit, proper shooting techniques and ammo selection that the size of the bore. That said, I will suggest a Mossberg 500 or Remington 870. Both are great guns and you can easily find additional barrels. Look at both 12g and 20g ones and figure out which one suits your wants and needs the best. While I like 16g and 28g shotguns, I would not recommend either as a first shotgun since, ammo selection is more limited.