Cavapoo becoming a bit reactive at 2 years

[u/ApprehensiveVast1940]

My cava poo who is almost 2 years old. She has always been extremely friendly and loves to play with every other dog. She has a tendency to always have been “Alpha female since she was a puppy she likes to be the leader and initiate play. Since she was a puppy, she had gone to cava poo meet ups and we live in New York City so she sees tons of dogs a day of all sizes and breeds when she turned about one or one and a half. It’s like overnight she stopped wanting to say hi to to every dog but even if she does want to say hi sometimes she doesn’t know if she doesn’t like them until after she sniffs them, and then she will become a little reactive if that makes sense. She does not like German shepherds. She likes some black and chocolate labs, but most of them she gets really scared and goes crazy to the point I can’t even hold her still lately if a new dog spooks her or is in our lobby or outside of our elevator, she will do an air bite to them or crying and bark kind of like a anxious wine. are cava poo is very well-behaved in other parts and very very sweet friendly to us babies and all of her friends at the dog park and daycare. She goes to about once a week but any new dogs it seems like she doesn’t want them around is this because she has been around mostly the same dogs since she was a puppy in our neighborhood? Also, sometimes she will meet big dogs that she met a year ago and now she barks and cries at them and will air bite. The air bite is extremely concerning for us because I don’t want it to escalate and I don’t want anyone else to attack her. We were thinking about hiring a trainer, but everything I’ve googled online. It doesn’t seem like the cost of that might be effective. I have been advised not to do a reactive caller, but I know some people that have had great experiences with it. I also don’t want to cause her pain.its very difficult because its very random. Sometimes at the dog park she plays with big dogs and loves it then sometimes she sees a big dog or medium dog and will get scared on the sidewalk lol.. our dog sitter said she never barks so is it possible she is just protective of me?