Abmer, learning to masturbate is a great way to learn to enjoy sex. In sex therapy, we always recommend guilded masturbation. You can't enjoy something with another person if you don't even understand how your body works and masturbation is the best way to do it. If you are looking for some educational videos and books, look at the Sinclair Institute. They are a religious group so some religious stuff comes up sometimes, but the materials they have are truely educational.
One of the first things to understand is that for women, you actually don't need penetration to have sex and orgasm. The clitoris is one of the most sensitive parts of the female genitalia and stimulating it will give you pleasant and you can orgasm. Do a google image search to see where it is as most text books and sex ed classes never show the clitoris.
Try to relax and enjoy your body, not just your genitals. Try to fantasize or just have sexy thoughts. Rub your vulva and get yourself excited. Rub your clit to get yourself aroused, maybe even try to have an orgasm. This will really relax your muscles and make you wet. Only then try inserting your fingers, one at a time. There is nothing wrong with feeling tight as long as it doesn't hurt. If anything hurts or doesn't feel pleasant, don't do it. Thats a sure way to make yourself tighten up again.