When the boys are watching Revenge of the Nerds, Sergi is wearing a tshirt that says Big Fun. This is a reference to the fictional band Big Fun in the movie Heathers. Heathers was released in 1988.
This one was edited from its original showing in October, 2017. The resume for Beverly is clearly changed from 1966 to present to the 1/31/18 re-airing now showing 1968 to present which alters the time for Erica entering college in 1986 instead of 1984. If you compare the two airings from blue-ray to Hulu, the edit is clearly noticeable.
While showing Murray her updated resume, Beverly's "experience" states that she has been Mom from 1966 to present. So that makes the year 1984 and Erica 17 or 18 in the fall of her freshman year at college.