There's always people whose cases get approved faster or slower.
When I submitted my I-751, the estimated time was 7 months. It took 20.5 months.
The funny part, a friend who is similar age as me, same immigration history, similar job etc submitted case 2 weeks later than me, and got approved 3-4 months faster than me. But there were people who waited even longer than me around same time. You'll get your approval, it's the last stretch 😊