Not worth it at that age. I did a similar class (My Gym) at 6 months, baby couldn't even crawl yet. It was cute to see her around other kids, but once I found that a church in town had a similar Mommy and Me class weekly for FREE, we didn't go back to My Gym. Until they are mobile and running around (closer to 2), it's not really that big of a deal. My kid climbs furniture like it's her job, and is an American Ninja Warrior on the playground, and that is all without paid infant/toddler gymnastics lessons.
One we figured out that paying $80/month for our baby's "gym membership" was a stupid idea, we just got a family membership to the YMCA ($111/month for the family) where the kid could socialize and play with other kids, while mom and dad could get exercise / shower privately / play on wifi in the smoothie cafe for 2 hours/day. Plus now our YMCA offers a Parent and Me class three mornings a week where the kids play exactly the same games they did at My Gym. That was a real win-win.