A lot of people from my work keep saying "don't get married young, that's how I ended up in this mess." One specifically told me that he's a good age (26) but I am not (22).
Pretend that the relationship, whatever the people's ages, is at that point where marriage is the next step.
edit: thanks everyone! this was the general thought I had, that it happens when you're ready, but the wise old ladies at work had me question that for a few. Silly traditions.