Expectations of children

Okay I have a step son, whose eight then I have my daughter whose 7 weeks. I’ve noticed my MIL and my spouse making a lot of remarks on expectations of my daughter...everything she does, or things she’s already started to learn they refer back to my step son when he was that age. Which is okay but what I am not so okay with is that they are saying stuff along the lines that he started walking at 7 months so they expect her to do the same but I’m not certain she will be walking at that young...I mean 7 months is pretty young and I read that a lot of babies normally start walking between 10-14 months... I feel under pressure myself because if she doesn’t, then they may look at me in a way of I’m not spending enough time teaching her. This is only one example of stuff they compare to or expect her to do because he did it at whatever age. I’m all for hearing stories about him, I adore it... but I feel like they are both individual people and will do things differently. I would never compare my daughter to someone else’s child and if it were vice versa or if she was closer to his age, I would treat them as two separate people and not base what she may have done to what he didn’t do or expect him to do something because she did.. and I guess that’s just common curtesy or respect to the children. It’s almost like when she smiled and I showed them, they rely like yep *step sons name* did that at 2 weeks when they know she’s already 6 weeks you know what I mean? I did mention it to my spouse and how I didn’t like the expectations given to her and he basically said that they are his kids, so she will do the same as her big brother and I got snappy and said his genetics have NOTHING to do with what age they crawl, sit up, walk, talk... and every baby learns at a different pace but it didn’t get anywhere and I’d be dammed to ever say anything to my MIL among the same lines to what I said to my spouse... I just wish we could appreciate each child separately...