Is my baby behind??

I gave birth to my baby last year early July, I was due the 28th of July, but my water broke and they weren't going to induce me after they checked me because I was 36 weeks, but I ended up having her and she's fine growing beautifully, but one thing I'm worried about is her meeting her milestones since she was considered a preemie she sits now and crawls and tries to climb and stand, but she hasn't said any words besides mama she's 9 months now and I'm just worried because last time at her 6 month appointment the Dr. Said she wasn't sitting and that her milestones were off :/ I'm just blaming myself a lot, my other child is older and he also was a late bloomer, but did meet his milestones, any ladies have any suggestions as how I can help my baby girl??