Bad Manners and Brimstone

But it is long and I agree with other posters that you should keep your first dance on the short side unless you bring in other people to join you on the dance floor.

I think 2-3 minutes is perfectly fine for a first dance. 30 seconds? In my opinion, is way too short.

I didn't mean that the dance should be no longer than 30 seconds, just that the time the couple is dancing alone shouldn't be too long.  The thirty second test is just to help us realize how long 30 seconds, a minute, two minutes, whatever, really feels like.

As others have said, it's often awkward when the first dance is just the HC the whole time, even if they are really good dancers who have practiced.  Same for father-daughter.  In my experience of a zillion weddings, it works way better when, after a short time, others join.  For example, if the HC starts, then perhaps the parents and siblings join, or the bridal party.  If it's a father-bride dance, then pretty soon let mother-groom join, then perhaps groom's father with bride's mother and/or siblings and/or grandparents.  Like that.  The particular combinations don't matter so much, just whatever works for your group. 

And then invite everyone else to join, because that makes it feel less like a performance everyone is expected to sit and watch and more like leading off the dancing.

The timing of when to invite the next group is best left to the band leader/DJ, who can read the room.  Fabulous, confident dancing, and the crowd is enjoying watching?  Let it go on awhile.  Awkward and shy dancers?  Rescue them sooner.

At my son's wedding, his college a capella group surprised the bride by singing the first dance for them rather than having the band play it.  But it was still the song the couple had chosen.  (And it still felt too long, and this was my own kid's wedding!    )

This is getting way off topic, but another special dance I've seen at a few weddings, sometimes starting with the First Dance, is to invite all the other married couples to the floor, start the dance, and then at intervals tell those who have been married less than five years (which of course includes the HC) to sit, then 10 years, and so forth.  The last couple left on the floor gets flowers (often the wedding bouquet, which fewer and fewer brides want to toss these days).  I have wondered if single/widowed/divorced people feel left out, but it seems like at a wedding, it is okay to recognize and celebrate marriage, especially now that same sex couples can marry, too.

Back to the original question: I repeat my original advice, which is that sentiment is great, but much more important is what will work best in terms of danceability.  Make sure it is one the band can do well, if you have live music.