Yoga classes for a senior citizen? [View All]

I feel like my mom needs to get out more and even though we talk on the phone once a week for at least an hour - that is not enough contact for her. So I was thinking for Mother's Day I would get her and myself yoga classes for like 6 weeks so we could have planned time together and she would get out of the house. She is in her early 70's.

She still does her own work around the house - raking, snowblowing, gardening, lawnmowing so I think she could handle yoga - BUT I have never taken a yoga class so I don't know if this would be relaxing, too strenuous or what.

Do any yoga people have advice? Are there some people who don't like yoga? I've never heard anything bad about it (except my SIL says a lot of people pass gas when they do it which I wouldn't look forward to).