Yes. Age does play a role early on and later on.
Insurance companies will tell you that the human brain is not even fully developed until the age of 25, so it would seem that people should hold off on the monumental decisions until their brain is fully developed. God knows that most people do not use much sense at all when it comes to romantic relationships, at least, perhaps, they should wait until their brain is fully functional. :0)
Please understand that there is a huge gap in age when one party is 28 and the other is 18. Not so, when the same 10-year gap is employed between someone who is 48 and their significant other is 38. It is about experience, character development, and emotional and psychological maturity, something that very few 18 year-old's possess.
It is also said by marriage counselors, that the farther away from your 20th birthday that you marry, the better your chances at having a successful marriage. And, I think a lot of that can be chalked-up to one's own character development, psychological and emotional maturity and experience.
The next issue with significant age-gaps is when one of the parties is substantially older than the other. Just recently I ran across a young lass, who I believe was 18, who is in a romantic relationship with a man who is 30 years her senior. Needless to say, if they have children (right away), the father will be 67 years old when their first child graduates from high school. I had a friend in high school whose father was 60 when he graduated, and there was virtually nothing they had in common and virtually no interaction between them.
It is also true that when this young gal is reaching her peak in life, her significant other would be nearing death's door or quite possibly exhibiting signs of illnesses and diseases that are common for the aged. This, too, can pose a problem. Perhaps when her old man needs her most, she will abandon him for better prospects, or he passes on...midway through her life or he becomes debilitated with disease.
Don't get me wrong, I am a proponent of love and good sense, but one must consider many things when contemplating romantic relationships and marriage. What may be fun and feels good today, may become a burden and nightmare tomorrow.