Air cadets and a RMR

Afternoon all,
Don’t know if this is the relevant area. I was just wondering if any one has looked into being in the royal marines reserves as you can join at the age of 17 and if this would be an issue in terms of attending cadets, obvious the reserves would take priority. Not to sure weather i’am talking a load of rubbish or if any one has done this, just interested it weather it would be possible or not being in both the ACO and the RMR.
Many thanks Luke