Well, the way I see it, any loving father will understand the problems his daughter goes through. If he loves you, he will be disappointed in you because you're so young, but at the same time, he will still love and care for you and support you in your time of need. If he loves you, then know in your heart that he won't stop caring.
As pertaining to your 2nd paragraph, I have no better advice to give than that of following your own heart. Young love is typically the same thing as young lust, so perhaps it'd be hard to trust somebody at that age. There's also the moral issue of whether or not to tell the real father of his imminent baby who beds in your womb. So, as I said, the only advice someone outside of your shoes can give, is to follow your own heart.
Patrick