Can someone help?

Eva • I`m 27 years old and I`m married. I'm the proud mama of a 1 year old beautiful baby girl and step mama to a 7 year old beautiful little girl. Baby girl #2 is on the way!
Can someone help me understand the percentiles? Today, at 26 weeks 4 days the doctor said based off my 20 week anatomy scan, my daughter is measuring in the 68th percentile. Is this good?