Yoga is for everybody. Really, everybody. It is so diverse that it offers the right approach and dosage for everyone. If you catch your thoughts circling around Yoga - may it be that you want to try it or may it be that you are convinced that Yoga is not your thing - as soon as Yoga has entered your mind, it is suitable for you. In our Western world Yoga is often very physical. I do admit that it usually needs a certain level of fitness to follow a common Yoga class. But every asana and every sequence can be adapted to the individual constitution of the practitioner. Therefore, in most Yoga classes, different levels of the same asana are suggested. Additionally, not every day is the same. Postures that were not approachable yesterday may be achievable today - and vice versa. Yoga is for everybody who is willing to observe her/himself.
If you are unsure about your level it may be a good idea to check it in a private class.