Hello,
I did attend some group classes at Reitschule Waldhof which is not too difficult to get to by public transport (catch a bus from the Zurich airport). The teacher basically integrated me into the existing groups. I went on Saturday mornings, had classes with around 3-4 other teenage girls who were about the same level. 6 was the maximum number of students. Lots of trotting exercises and directional switches which was suitable for me, although when I had private classes in Malaysia the teacher did cantering with me each class.
Class was in Swiss German, but the teacher would throw English in here and there so that I would understand the instructions. Overall I thought it was a good price for 1 hour worth of exercise (it was around 40CHF or less if bought as an abonnement). But I wasn't really progressing much as a rider, so I have stopped going. Partly my fault because I wasn't going consistently, and so my muscles never had a chance to build... I've decided to change sports now to mountain biking as this is something I can do every day or every weekend, without paying each time!!!
But do give this place a try. I heard from another friend about one in Buchs, also 45 mins from Zurich, but they had up to 10 students in their group lesson!!
Sadly I already invested in two pairs of jodhpur pants which have hardly been used. One was too small for me so I used it once and never again

in case anyone reading this has teenagers and need size 26-28 (teen size), please PM me and we can strike a deal