I am a Muslim boy of the age 19. I have searched for this answer on many sites, but have found nil. I am writing in hope that someone would guide me on this issue. Can a Muslim boy marry a Christian Catholic girl? Should the girl convert before marriage itself or can she do it after marriage too? Can she practise her religion itself?
All praises is indeed due to Allah SWT blessing and salutations upon Muhammad (PBUH) and all his companions, his family members and his entire household.
Marriage is a topic which everybody likes up if we hear it. The Prophet (PBUH) guaranteed Paradise to those who will guarantee him correct use of what is between cheeks and the correct use of what is between thighs. In fact it sounds easy but all our life rotating around these things.
According to Quran muslim man can marry christian girl:
This day [all] good foods have been made lawful, and the food of those who were given the Scripture is lawful for you and your food is lawful for them. And [lawful in marriage are] chaste women from among the believers and chaste women from among those who were given the Scripture before you, when you have given them their due compensation, desiring chastity, not unlawful sexual intercourse or taking [secret] lovers. And whoever denies the faith - his work has become worthless, and he, in the Hereafter, will be among the losers. (Surat Al-Mā'idah, 5:5)
But also take into account that nowadays a lot of christians are considered polytheists because of the trinity. So we can apply next ayat:
And do not marry polytheistic women until they believe. And a believing slave woman is better than a polytheist, even though she might please you. And do not marry polytheistic men [to your women] until they believe. And a believing slave is better than a polytheist, even though he might please you. Those invite [you] to the Fire, but Allah invites to Paradise and to forgiveness, by His permission. And He makes clear His verses to the people that perhaps they may remember. (Surat Al-Baqarah, 2:221)
Okay, but even if she is a chaste woman and she is a good christian (not a strip-dancer and so on) ask yourself 2 questions:
Do you really want that your children will be brought up by a christian woman. Are you sure that they will become truthful, good muslims?
Are you really sure that you love her for the sake of Allah SWT, not for her pretty good "shapes"?
Once I was in pretty the same situation and usually I tried to avoid these questions. But when I honestly answered them I decided that it will be better if I will not be so pleased with her beauty and her "shapes" but at least Allah will be pleased with me and my decision. And this is enough for me.
And of course Allah knows best. Just make Istikhaarah, ask Allah to guide you and to help you to make a right decision.