It depends if you want a relationship with her or not - not about what other may or may not think of you if you don't go.

If you would rather keep your distance and let the relationship stay where it is at the moment, then don't go. Just be aware that of course there will be ramifications - missing your daughter's engagement party is a pretty big thing to miss.

No-one can tell you what the RIGHT thing to do is. No-one, other than you, knows the history so as I said, it really depends on whether you want a relationship with her or not at the moment.

At the end of the day, you have to trust your own judgement and hang everyone else's two cents.