Character meets are not and should not be "only for kids." I'm not sure what search term to recommend, but there have been lots of threads on the DIS about adults meeting characters; lots of us do it!
I've met lots of characters and had lots of great experiences, with the characters and their CM handlers. If any other guests have ever given me the stink-eye, I haven't noticed. If there is someone you want to meet, go for it! I think the characters enjoy it when they know you're a fan. Not to rehash all my favorite stories, but when I told Dug and Russell they were my heroes and their story was one of my favorite stories ever, they made a big fuss over me, and Russell was ready to go home with me (Dug would have, but he didn't like hearing he'd have to fly on a plane.) Every year I go visit Phineas and Ferb 'cause I love them; this year, i wore my "Phineas outfit" (orange & white striped T, dark blue capris, black socks and black & white sneakers) and they loved it; I told them it was my outfit from their "Summer All the Time" fashion collection (a P&F episode). I got lots of hugs and kisses that day.
We had a conversation here before about some of the Princesses being a little stiffer than others - My favorite meet & greet Princess is Tiana. I've met her twice with different "friends," and she is great, friendly and chatty (I think because she's 20th Century royalty she can be more relaxed).
Trust me, I am the silly middle-aged lady who went solo to Hollywood & Vine for breakfast because Doc McStuffins was exclusively there, and the characters and CMs were super-sweet! Don't be shy about characters.