if you still have eligibility (you burn eligibility while in college even if youre not on a team, but if you graduated in 4 years, you still have a year of eligibility) you can wrestle in grad school, its done all the time. if you graduated in 5 years, sorry its over. read below.
as for whether you can compete, how should i know? its certainly not out of the realm of possibility. sometimes i think time away makes you better.
breakdown of eligibility rules:
14.2.1 Five-Year Rule - A student-athlete shall complete his or her seasons of participation within five calendar years from the beginning of the semester or quarter in which the student-athlete first registered for a minimum full-time program of studies in a collegiate institution, with time spent in the armed services, on official church missions or with recognized foreign aid services of the U.S. government being excepted. For foreign students, service in the armed forces or on an official church mission of the student's home country is considered equivalent to such service in the United States.
14.2.3.5 Participation after 21st Birthday - Any participation as an individual or a team representative in organized sports competition by a student during each 12-month period after the student's 21st birthday and prior to initial full-time enrollment in a collegiate institution shall count as one year of varsity competition in that sport. Participation in organized competition during time spent in the U.S. armed services shall be excepted.
To summarize the Five-Year rule, enrolling at college or university full time begins your five-year eligibility clock. For a player aiming at the NCAA, full-time enrolment could make them less attractive to schools/coaches recruiting future talent - by thus having less years to work with the player. For the most part, players that want to continue schooling while playing out their junior will attend as part-time students. This allows them to keep the edge on their studies while also being able to balance the rigors of playing junior hockey all the while keeping their NCAA eligibility intact.
The second rule above may or may not be an issue for some players. In some cases, a player will turn 21 during their last year of junior. If so, a player cannot continue playing once their 21st birthday occurs if they are inline for the NCAA the following season. If they do continue to play, the player will lose a year of eligibility - again something that most coaches aren't that keen on when recruiting a prospective athlete.