I agree with Dr Povolny, you should strongly consider passing on Invisalign for a treatment option. Unless, you are comfortable writing a big check and getting little to nothing in return.
That said I had one patient who only wore them to bed and a few hours every day. She transferred into me from another city. Both the other orthodontists and myself strongly warned against it. I have to confess she got about 90% of what she hoped out of her treatment. It just took 3 times as long.
I think the key to her success was she was very consistent with her hours and was in her mid 20's. The reason the age plays a factor it simply the bone density factor. Typically the older the more dense your bone, so moving teeth is harder and less predictable.
If you use simple math to think about this and apply some basic science...we are talking about moving something throw bone. Bones cells have to be stimulated enough to be broken down, pushed out of the way to allow the tooth to move. Then the tooth needs to be held there while the bone cells fill in around the tooth's new position and harden. That take TIME. There are 24 hours in a day. So theoretically, 12 hours in and 12 hours out = a net zero.
I think your key, if you still really want to try Invisalign is being truthful, as you seem to be, about the wear you will be able to get AND finding someone willing to try it with you.
Congrats to you on realizing you have a full life of beautiful smiles ahead of you and you deserve it.