I'm a new fan of the series just started watching season 2 and I was wondering do we ever meet Jo's mother?

Yes, we do. She was played by Claire Malis, but you'll have to wait a few seasons to "meet" her. She appears in a few season 4 episodes and a few times in season 5 as well.

She also appears in the season seven college graduation episode.

I don't think she ever appeared alone. Charlie was always with her.

She also appears in the season seven college graduation episode.

Actually, Season 8 when Jo graduates from college, but her very last appearance on FOL was "Till Marriage Do Us Part" where Jo and Rick get married.