In the UK at least, marrying under the age of 18 is almost unheard of (about 3000 people in 2013, stats here), that’s about 0.6% of all the marriages that year. Most people get married in their late twenties or early thirties (you know, once you’re an adult).
Mind you, marriage rates have been dropping here since the 1970’s, and 70% of marriages are civil partnerships, as opposed to religious.
So if by “people of European descent” you mean Europeans, nope, we don’t get married that early, and we don’t do it because “god told us to”.
