We can say there are two different kinds of fluid in the vagina. One is mucus produced from the cervix, which changes its amount, stickiness, colour or smell over one menstrual cycle. This is also known as Vaginal Discharge. The other one is secreted during sexual arousal. When you're sexually aroused, blood flow to the vagina, vulva, and clitoris increases and this causes swelling. Then, the vaginal fluid is secreted from the wall of the vagina and moistens the surface to prepare for penetration.
There could be many reasons causing vaginal dryness. For example,
Women who have never had sex before, tend to be too nervous, even afraid of the first experience. They are not in the right mood to enjoy arousal, and often their partner also doesn't have much experience and rushes to penetrate without having enough foreplay. This contributes to the pain of "losing virginity". This painful experience might even give her a fear for sex thereafter, and which could then cause vaginal dryness.
Sometimes, vaginal dryness suddenly happens to women who usually don't have this problem. External influences can be one of the reason, which is usually medication. If you're taking birth control pills and notice the dryness, you may ask your doctor to prescribe a different pill. Or even a full stomach could be the reason. It's said that when your brain is satisfied with a good amount of food, your sexual sensitiveness will be dull so that you might not be able to get aroused enough.
If you don't have much experience, it's always good to practice. Masturbation will help you to know your body better. You will find where your arousing spot is, and see how much and when you get wet. Once you can enjoy masturbation, the sex with your partner will be more pleasurable.
Does your partner give you enough foreplay? If not, it is surely very difficult to get wet. Ask your partner for oral sex, which makes your vagina moist with his saliva. The softness of a tongue won't hurt you.
Some women tell that they are not keen to use lubricant because their partner might worry they're not good enough for sex. Or, their partner might think they're sexually insensitive. But as we have seen all those reasons above, this can happen to all of us. Just like every man has a chance of an erection problem. And there's nothing bad about using a lubricant. Lubricant is slightly viscous and texture is very soft. Put a drop of lube on the finger tip is a good test, and you can then put a lavish amount on his penis and give him a hand-job before penetration.