I’m afraid I’m always going to resent mil

Please tell me it gets better. When my LO (now 2 yrs old) was born, my mil held him at 5 days old and said to him and she knew I was sitting right there “I hope your mom knows your first word won’t be mama, it’ll be dada. All babies say dada first.” I figured she was just trying to fool around a bit so I laughed and shrugged it off. Then she said it again very shortly after “your first word won’t be mama, your first word will be dada.” Again I smiled it off thinking she’s just teasing me. Then again, this time to me, “you know his first word won’t be mama, right?” Then again “his first word won’t be mama” by this time I just ignored her and pretended I didn’t even hear her. She stopped saying it. Today she was trying to get LO to “can you say grandpa? Can you say grandma?” And I could just feel by blood boiling. BEC right? Because what a normal thing for a child to say. But I resent her so much. How dare she say those things to me over and over and over when I was just a week, a month, 2 months pp and then constantly badger my toddler to say “grandma” and be so delighted by it. She made me feel like I didn’t matter as soon as I popped the baby out. I feel such anger thinking about this. Please tell me resentment like this goes away. Please help me look past this. Don’t ask where SO was when all this was happening. He’s oblivious.