Nothing beats having a coach's guidance!
Every adult class is different. I have found quite often that the class ends up catering to the present athletes to some extent. So if most of the athletes who have been going to the class prefer to work mostly independently, the class tends to reflect that.
If you would like the class to be a certain way or to cater to your needs, ask! The worst that will happen is they will not be able to accomodate you. I find that many instructors don't think adults want to be told what to do (i.e. be coached!) in gymnastics. However, if you want that, let them know. Others may want it too but just be too shy to speak up.
Always show appreciation that the class exists while asking for tweaks to be made in how it's run, and you can't lose :)
And lastly, afraid you can't handle an adult gymnastics class? Get inspired by reading this story from a diabetic adult gymnast.