Do you try to stop your daughter from getting married?

“My daughter has been with her boyfriend for two years and they graduated from high school over the Summer.
He proposed to her on Valentines Day and she said yes. I’m worried that they’re going too fast and they’re too young.
How do I bring up my concerns without coming off that I’m telling her how to live her life?
I don’t want to see her make a mistake she’s going to regret.”