Kaylets, methinkest thou suffereth a little from a disease I also, er, suffer from. It's called "I'm absolutely sure I did/said/came across wrong in that discussion/interview/situation ..." of course, for me, it keeps escalating (I don't see you doing this as much) and after I analyze everything I said/did/came across wrong in, it starts down the slippery slope to "I'm no good, will never be any good, have no future and it's all because I can never say/do/be the right thing."
Job interviews are the worst causers of a flare-up of this condition, but be assured there's no way for you to know what the woman was thinking of you ... even if she WAS thinking about you and not just wanting to go home to dinner and a good book. But you did get a better vibe from the supervisor and it's more likely the supervisor who will truly decide who gets the job.
I've had lots of interviews where they didn't know I was coming for some stupid reason or other; once I got offered a job when I was at a place for another reason ... one I won't go into, but it wasn't a positive reason. You just can't predict the outcome of these things and rest assured if you don't get the job it won't be because of any mud on your pants or anything you said or didn't say ... just the luck of the draw in most instances.
I DO think that unspoken "why are you looking at this low level at your age" question is a common thing. It's a reflection of other people's egos about what they perceive themselves to have achieved and it is meaningless. "Level" means nothing. Age means nothing. You are looking for a work experience that is good for YOU and to be an asset to THEM. You are not a career-seeking missile programmed to hit specific targets or conform to patterns created by others.
Make dang sure they know that.
I bet you did really well and if you don't get the job, well, it's their loss.
Rock on.
I gained .60 of a pound this week but am not unhappy considering I've been eating for two (me and the virus) and not exercising.
Time to move on.