Hmmm, it would make me leery to hear I was someone's "new BFF". Doesn't that mean best friend forever? It kind of implies there have been previous BFFs. I guess those weren't so "forever" if you are the new one! I do hear your concern, MUE. I think you're doing fine to set your boundaries. You've told her this weekend is for your daughter--not a big deal. They should be able to handle meeting without you. It's nice they all like you. Sometimes people who don't have kids don't realize how much planning goes into being able to attend an event without one's child--having to arrange a baby sitter, make sure there is enough cash to be able to pay for one, preparing the food in advance for the child's meal, etc. When my kids were little, it was only on very rare occasions that I paid for a sitter. Just stayed home with the kids a lot. Or had other friends over who also had kids, so they could play together while the adults had some grown-up time. Or met up at playgrounds on weekends, etc. It sounds like you would like to help with your friend's project, but the project meetings don't sound super efficient and are more like social events combined with some work. So your expectations about spending a certain set amount of time helping with the project may not fit into the fun+work type of event the meetings really are.

Since the new friend lives so close, maybe you can have some shorter, less meeting-like interactions--like sharing coffee together one day at one or the other of your homes. Or walking together in the neighborhood on a sunny day with your child in a stroller (not sure how old your child is?). Something with less expectation and commitment--you know what I mean? You wouldn't have the expectation of such a get-together that it would be a time to get project work done. You could just try to enjoy the company of your new friend, learn more about her, see if she reciprocates that kind of interest, and let the relationship develop (or not).