There are plenty of ukulele players who use a capo...if you use one, you just need to accept that intonation may be farther off than it was, and of course, the ukulele will have even less "bass" and some chords can be difficult to play on the smaller frets. That said, it can make playing in certain keys a much better scenario.
While some people will say there are rules about ukulele...I would encourage you to do what works for you.