I have this question that is bugging me. This may not be the place for it, but it was the only place where this seemed relevant. I've gotten pretty close with a girl, and she has said she's not a Christian, but a pagan. Would it be considered blasphamy for me to like her, and go further than being just friends?
No, it is not blasphemy. However, it is to be avoided. I know stories of Christians who have fallen in love with and got married to non-Christians or (even worse) false Christians (yes, false Christians may be even worse because you may not even see the threat before it is too late: in this group, we can include Catholics, Mormons, Jehovah's Witnesses, relativists, supporters of homosexuality, radical feminists, etc.); they ended up badly.
Think about it: suppose you are married to a non-Christian girl. Think of the following problems:
- You want to take your kids to church, but she refuses;
- You want to make a daily devotional, but she rejects that;
- She goes behind your back to ‘unteach’ your children all you have taught them;
- She uses inappropriate language in front of your kids;
- She uses God's name in vain;
- She refuses to go to church with you;
- She, secretly or not, ridicules your beliefs;
- She refuses to submit herself to you (as she ought to, in accordance with Ephesians 5:22-24) and instead attempts to usurp the authority given to you.
Now, think about this: suppose you are dating a non-Christian girl (not yet married). Think of the following problems:
- She seduces you to have sex with her;
- You want your relationship to be a way of serving God, but she does not.
And I'm not done! Now, consider this: suppose you have got married to a Christian woman, and now you have both died. Now, you are in Heaven, and you can see the girl whom you have loved all your life burning there in Hell, and there is nothing you can do to help; you tried to get her out of there, but she refused, and now she is suffering the consequences.
Or, worse still, consider the possibility that you may even be influenced by her beliefs and turn away from God!
I know that it is difficult, if you love a girl, to simply say that it cannot be and refuse to ask her to date you — but this is what you must do. I have been in your situation many times. There was one girl in particular with whom this happened almost two years ago. I asked her to be my girlfriend, but she said no. Currently, I am so thankful that God did not allow me to date her, instead protecting me from this danger. I was so blinded by my passion that I could not see the seriousness of the situation I wanted to get myself into.
Control your passion for her. Come on! I know that you can do it!

You can resist that temptation. It would not be good for you. Ask God to help you control it, and to show you a Christian girl with whom he wants you to date. You can do it! With God on your side, you can be strong!
God bless you!
The Portuguese Baptist