A: There is no absolute reason why a relationship with this age difference cannot be very successful. It is interesting that if your genders were reversed and this were occurring in Hollywood, age would not even be an issue. Many leading men not only star in films with female characters half their age as love interests, but they also marry much younger women in real life. So this problem is primarily cultural and gender-based.
Some might argue that even if the age difference between the two of you is not a problem now, it will eventually become one, but the fact is that no one is in a position to know what the future holds for anyone. Some people contract debilitating illnesses; some people are vital well into their later years; there can be an unexpected death, and countless other unknowns. So to base your decision on what might happen in the future is not, in our opinion, reasonable, practical, or spiritual.
As to your father's heart condition, there are ways to consider his, as well as your own, happiness. We did not tell either of our families when we got married because we thought it would be too jolting to them. Instead, we quietly got married on our own, took the time needed to prepare them for the idea, and then held a second service when our families were more comfortable. We are not suggesting that you follow our example, but we want you to realize that there are many options, and you can choose one that would be kind to your father.
Since there are so many unknowns in your situation, it would be best to make only those decisions based on what you know to be true today. God is a very present help in times of difficulty, and present help is really the only help there is, since it never stops being now. So our advice would be to do today what your peace and stillness counsel. In the quiet of your heart, without regard to what might or might not happen, what do you feel most comfortable doing today? If you will take each step in gentleness and peace, gentleness and peace will be part of the outcome.