N.J.
My oldest son just turned 5-- and still has a hard time 'reaching'. And he often needs me to help clean up after the fact, but we're getting there. I think it all depends tho' because my 3 year old does a really really good job, so who knows (he does a kind of side wipe to reach, my 5 yr old just isn't getting that technique)
I was just told a good trick tho to make it easier, if you don't want to spend the $$ or risk your toilets from getting clogged with all those 'flushable' wipes. If you spread a little bit of vaseline on the toilet paper (if you trust her doing it on her own, my son is pretty good with it) it does a good job of cleaning like the wipes. Just a fun tip I wish I would have known about when we started training my oldest :)