Good news you are thinking of AA.
A sponsor is someone who has been sober a while and has worked through the 12 steps of the AA programme with a sponsor themselves.Somebody of the same sex.
If you go to the meetings you will understand more,there are no set ways of doing things in AA.
When I first started at the meetings the lady I asked to sponsor me had been sober 9 years,her sponsor had been sober 13 years then.Today they have 20 and 24 years sobriety and I have almost 11 years,it works as you can see.