Sister, let me give you some advice from someone who's been at the place where you are now, and who completely understands what you're going through.
First of all, you need to think. Think very very deeply of what you're doing. Think of the life you want in the future. Not the life one or two years later, but the life until your death. You've grown up as a muslim. Surely, you want your children to grow up as muslims too right? You want your children to be better muslims than you are, right? For that you need someone who is as strong in deen as you are. In the months of Ramadan, when its time to get up for sehri, you try to get up from bed, and its a little difficult. You need someone who can say to you "come on, get up. We have to get up right now and fast for the whole day." Will this person be able to say this to you after you're married, or will you be the one who will be persuading him to fast and get up early in Ramadan. Would you be happy to be getting up alone in those mornings? Wouldn't it be better to have a partner who you can share these things with, who can understand all of these Islam's little nuances? If sometimes you're doing something that's not in Islam, wouldn't you want him to be encouraging you to do the right thing, and telling you to stay away from harmful things? Would you have fun going to family parties and functions with this person, where all your friends are gathered with their own husbands? Will you feel like you fit in completely, and joking about your old jokes? Is this the life you want? Then when its prayer time, but at the same time, you have something else very very important to do. If you say "Can I just first go and pray, time's nearly over." Will this person say "yes, of course, go quick. What were you doing all this time?" like a good muslim husband, or will he say "Time's almost up anyway, you can pray later. Hurry up and do this other thing first." Which would you want?
Then, what about your children? Do you want to be the only one who enforces Islam on them, and is strict with them to do the right thing? You want them to learn things how you were taught, and your husband would want them to learn things the way he was taught. There's going to be a big big difference here, with both of you having grown up in spiritually different environments. Do you want a peaceful life where both you and your husband are complete partners in every step of life, or just a person who is different from you, and you'll be the one in the corner trying to take life forward in your own way.
Then, just saying to convert to Islam isn't enough. If you want to marry this person, you'll want this person to believe in the same things you believe in with equal or more conviction than you do. He must believe every aspect from within, from within his heart. If he converts to Islam and vows to live every aspect of life by it, then all's well and good, but I've seen countless couples just convert to Islam by name, but they're still in their western lifestyle, and their children have therefore no Islamic light on them. The children grow up confused, and eventually shed religion as well.
So think what you yourself would want. I've been through this, and remember, pray to Allah to guide you. Pray to show you the right way. Think deeply about everything. What do you want in future? Will this person be able to give it to you?