Acer from seed

This acer is in it's third year. It looks healthy enough but a little damaged from being whacked against the fence when the wind was in the wrong direction.
It's looking a bit spindly to me. Should I be doing anything or should I leave it to go its own way?

 

I think I would leave it alone, just make sure it gets some good light but maybe not intense heat.
It looks healthy.

 

I'd leave it. It may bleed if pruned while in leaf. A repotting to the next size up may be worthwhile, but not urgent by any means. I find there's always a bit of die-back on the tips of the branches, but you can remove any you see in winter - they're easy to spot from normal twigs and will be black or grey. Here's mine, grown from seed:

 

I agree, the ones I've grown from seed have all been very slow to begin with but then suddenly explode with growth. I don't think that's too shabby for a 3 year old seedling.