Is it okay for a male to not be turned on by vaginal sex, but only by oral (cunnilingus and blow job)? If it's not, then what can I do about it? I'm a virgin 20 years old and I'm worried about it. How can I get my woman pregnant completely without desire in conventional sex?
I think your perspective as a virgin is what makes you think this. You know what oral feels like so it’s a familiar feeling, and safe. Until you actually have vaginal sex you just don’t know so it’s an unknown and can make you hesitant. Oral is great but the closeness of vaginal sex is unmatched.
Dude, you're a 20yo virgin. You're scared shitless and have...Performance Anxiety™! You are so worried about how you'll perform that you can't perform. (I'm just rephrasing what Longzi said.) Happens all the time. Confide in your partner (as per Zen) and she can help. Don't fixate on fucking. Take it off the table, as a goal. Just be playful and sexy and loving and see what happens. And men can need foreplay, too. Or make outercourse your goal. "Dry hump" her, with your cock between her labia but outside of her vagina. For that exercise, her vagina is a "no-fly zone". Or spice it up with some erotic play. Toys, games, lite D/s. The goal is to get your mind off the penis-in-vagina fucking. That can happen by upping the pleasure and distracting with other goals. One thing that will not work is instructing you to not think about it. So I won't. Don't tell yourself that, either. That would be like telling a person deep inside a large forest to NOT think of bears. He's gonna think about bears twice as hard. A supportive partner, a bit of distraction and some patience will get you over the hurdle. You have a lot to learn, but you will, Grasshopper, you will.