Am I (18F) being too sensitive to a comment made by my boyfriend?s (18M) mother?

For context, my boyfriend?s (let?s call him Jack) family have an annual Christmas party with families that my boyfriend and his siblings went to primary school and toddler play groups with. As my boyfriend and I have been dating for nearly 9 months he thought it natural to invite me and I had a relatively good time despite me hating family gatherings such as this.
One of the guests was a daughter in one of the families who is the same age as my boyfriend and I and was in his class up until she got held back a year when they were about 11 or something. For arguments sake, her name is Jane. She is pretty and very good at the family gathering spiel and has known my boyfriend?s family for a long time.
At the end of the night (I was spending the night), after everyone had left, my boyfriend?s mother sat down next to us on the sofa and said, ?Well, Jack, what did you think of Jane, huh??, in a very drawn out, playful tone, wagging her eyebrows. My boyfriend replied ?What?? and his mother said, ?Her appearance. What do you think of how she looks now? Awfully grown up compared to last year right??. Jack said he didn?t see anything different and his mother started talking about something else.
When I brought this up to Jack he said he didn?t think his mother meant anything by it but it still makes me angry when I think about it. Did she deliberately say that because I was right there? Did I completely misread the situation or? I feel like it was a big dig in the ribs to me as perhaps I?m not the one she wants her son spending all his time with.
EDIT After talking with my boyfriend, he did tell me he brought this up with his mom (without saying anything about me) by saying it just made him cringe and maybe she shouldn?t have said it. She said she thought since the two of them had known each other so long he?d have something to say.


Source.