Go for it. Vaginas are incredibly elastic and snap back to their natural size within hours/a day of sex. Learning about yourself and what gets you off is really important to your future sex life. If you don't know how to get yourself off, how will you be able to help someone else do so?
Sex won't be as painful the first time you have it, mostly because you'll already know what to expect and your hymen is already broken. My first time didn't hurt at all, and I had never used a vibrator or dildo beforehand. My suggestion would be to get a vibrator/dildo (shaped like a penis, but it vibrates) because it will be more versatile and because 80% of women need clitoral stimulation (rather than just penetration) to get off.
Explore and enjoy!