Hey there!
If they're 2,000 in their time, then they must have went through 2,000 months given that they aged 1 year/month.
That means we're converting 2,000 months into years.
Because 12 months is a year, we divide 2,000 into groups of 12 (2,000/12)
to get 166 as our closest whole number. 12 times 166 is 1,992, so the remainder is 8 months.
Therefore, the aliens are 166 years and 8 months in human time.
Hope this helps!