Heh, well it's worth just getting to grips with moving and attacking first, which the single player will help with, though the AI won't help much with strategy unless you're setting the AI to specific behaviours to work on certain situations :3
I made much the same mistake with Palutena by jumping online with her before i'd really got to grips with her and lost a lot of matches initially. The temptation to jump back on my vet (Zelda) and show people I knew what i was doing was always at the back of my mind, but for the most part I toughed it out and got the hang of her

Some people do better jumping in the deep end though ;D
The key things are:
a) You're noticing new tricks or identifying problems and working to find solutions for them
b) You gotta have fun :3
As long as both those are true, do whatever you must