When my daughter Sarah was not much more than a pair of scuffed kneecaps and a set of pigtails, someone asked me "What would you say to her if in a few years' time she came home and announced that she was going to marry a black man?" Now, me being a tolerant, unbigoted, prejudice-free, noble etc person gave what today I guess would be called a politically-correct answer. But there is no doubt that my true reaction deep inside me was "Don't do it!" and I spent a long time - and have spent a long time - working out why. And I will tell you why.
Quite simply, it is a hard hard business to make a marriage work. All sorts of factors create centrifugal tensions: money, children, in-laws, habits, ambitions, sex, and so on. If you are married, go on, tell me I am wrong. No, I am not wrong. So, every additional factor you add into the equation is another potential source of conflict. So, for example, marrying across race, religion, nationality or culture is adding a dimension, as is marrying someone much much younger or older than yourself. That is not to say you shouldn't do it, but it is important to be aware of what you are doing. Once you are aware, I guess your chances of making a good marriage - or a bad one - are just the same as everyone else's.
That is the answer I should have given. But, you know me, l'esprit de l'escalier. I am just a slow reactor. If I bang my knee, it's at least forty seconds before I cry "Ouch". But it's all academic, as my children - just like you and just like yours and just as I did - do what they like anyway.
Of course, the most devastating difference when you decide to marry is that one of you is a man and the other of you is a woman. Work through that.