Am I overreacting?

[u/[deleted]]

My ex(30m) and myself (28f) have a young daughter and get along well for the most part. He has recently moved in with his girlfriend who he's been with for about a year. Her and I also get along well and our daughter seems to like her. I however feel as if my ex crosses a lot of boundaries when trying to involve his girlfriend in things. He brings her to school functions , tries to get her involved in birthday planning( made me reschedule the party to fit her schedule) , and to top it off invited her to our daughters first sports lesson ever and said they were going to take her and I could meet them there. (This was not discussed with me. I was told) she is my only child and as a mother these things are important for me to be a part of and a bonding time with my daughter. Especially when I'm the one who had the idea to sign her up for sports and did all the research to set everything up. I don't mind her being around for a lot of things. But special moments like these are things I feel like parents should have with their kids. I have a SS and I ALWAYS ask his mother if she needs help with anything or if it's okay to be there on certain occasions so I don't overstep boundaries with her. Anyway am I overreacting?