Dressing girls alike?

So I have a 15 month old daughter and I’m 24 weeks with another girly.

I bought some clothes which was in both her next size and for when baby comes so they can dress the same on the odd occasions. I mean it’s my baby I can dress them how I want right?

My MIL thinks I’m stupid for doing so she said they will look stupid they ain’t twins. I’m not making them things fgs I said but she just replied I would never have done that. ( she doesn’t have two the same sex children anyways) she said well make sure they dress different when I have them or I won’t take them out. She never fricking looks after my daughter I have now as she can’t cope with her at nap time.

Am I wrong for wanting to dress them alike?.