I would second Amanda Steege - really great horse woman and has a fabulous way with horses.
I believe Emil also has a lot of adults but I cannot speak to his barn directly other than I’ve had friends who are happy there and seen other posters recommend.
A suggestion might also be to talk directly with your trainer re: wanting to be a barn with more Ammies and/or just looking for some additional input or your desire to jump up a level of competition. Being with the same trainer forever can be great but can also get stale so it’s sort of natural to want to get advice from others as is wanting to further your riding.
She might totally get that in addition to working with her you might also like to work with someone else and/or if you really do want to move up a circuit. One way to phrase this is that you’d like to try a different horse show than one that is normally on her list - i.e. I’ve always wanted to go to Kentucky or VT or Saugerties (or fill in blank) for a few weeks - would you be willing to support me in finding someone to go with (and have some ideas of who you’d like to go with already 
Doing this will allow you to see more and also test out someone who you might decide is a better fit.