I bought a 5 door GTI as we have a little one, my missus has a sportback A3 that our daughter spends most of her time in but I wanted a car that I could also use. It's the first 5 door I've had and it's been brilliant. Maybe when she's a bit bigger I'll go back to 3drs but for now I'd keep in looking if I were you..
A 5dr makes life so much easier.