Standard Maleficent Response here:
if you are grown enough to be having sex.. you are grown enough to be talking to her about birth control options. However, don't be surprised if she smacks you upside the head if you use as your excuse -- you waaaaant sex without a condom because it juuust feeeels better... (sorry - dated a guy who used to whine about that...
Suggest that you both get tested for STDS (again, your grown enough to be having sex.. you aren't having sex without a condom unless you know it's safe to) and then discussing options for birth control because condoms aren't overly effective...