Regarding dating somone from another denomination, I have been married twice and in both cases it was to a Lutheran woman. I now find myself single, again meaning I am twice divorced and annulled. Personally, I have vowed to only date within the faith from now on. I used to say that you could put me in a room with 50 women, 49 Catholic and one Lutheran and I would always fall for the Lutheran girl!
More seriously, I have come to think that Catholic women tend to take "...till death do us part..." more seriously than did the Lutheran women I have been wed to. You see, in my case, it was my wife who initiated the divorce both times. In both cases I was willing to stay unhappily married and they were not.
So depending on what you are looking for in the relationship and before it gets really serious, you guys need to have a conversation about it. As an aside, my dad converted to Catholicism during WWII, while dating my mother, and didn't tell her he had converted until after she agreed that she really loved him and would marry him even if he remained Protestant! When she said she would, he told her he had been taking instruction and was converting! Their marriage lasted 63 years; until death did them part...
It's great that your parents' marriage lasted 63 years, but that was a different time with different values. Today we live in a superficial culture that values quickie divorces rather than lifelong marriages.