He is only 26 ... which may be ‘getting on a bit’ in terms of tennis, but back in the real world, is still pretty young to get hitched.
I make no comment on Andy Murray personally, but it's interesting to hear someone saying that 26 is "pretty young" to get married, as mainstream media comment.
In the contemporary West, it appears that permanent teenager-hood is the ideal held out to us. It begins at about 8, as school, media and sadly often parents push you into it prematurely; it can either end somewhere just short of 40 when you hear the fertility clock ticking, or it can extend permanently into a very sad (as in, pathetic) old age (think of: ugly, silly old men strutting around stages with guitars like they did in the 1960s or 70s). The media actually holds that out as an ideal to aim for - still rocking at 70, yeah!
But... striking cool poses in the newspapers (for the select few) is no compensation for investing your life in something that tells for future generations (look at the family lives of those ageing rockers, and you'll want to run a mile...), or for eternity.
Permanent immaturity is not praiseworthy; the fact that so many think it so is a sign of the darkness of mind that God has judged our decadent societies with.