TL:DR - AITA for thinking it’s uncomfortable to hang out with the late boyfriend’s family while she has not introduced me to her actual family?

My girlfriend lost her boyfriend (while dating) unexpectedly a 3 years ago, and she still maintains contact with his family. While I understand that “family” doesn’t always have a clear-cut definition, I sometimes feel as though I’m living in his shadow or being treated as a replacement. I’m not sure if this feeling is valid, as my priority is her happiness. We’ve been dating for a little under a year, and she recently invited me to her late boyfriend’s family’s Thanksgiving. However, I haven’t met her own family yet, nor was I invited to her family’s Thanksgiving celebration.