Welcome to CB!
There are sooooo many things that goes into the factor of the score that only knowing about 1 account won't be enough to figure this out. Also, the late payments will continue to report for 7 years legally, but that is not the only thing factoring into your score, and it will also hurt your score less over time.
What other accounts do you have?
What is your UTI/credit limits?
How old are your accounts?
What else might have happened (such as an older closed account aging off your report)?
What score are you looking at? (Is it a FICO score or a Vantage skore)?
I'm sure others will think of other things to ask, but that is a start.