Of course it's an amateur time: You're not going to win any serious marathons running a 2:30, and if you have no chance to win, you can't really be described as a "professional". But c'mon, 2:30 is an amazing time for an amateur. Obviously it's "achievable", since maybe a dozen "amateur" runners managed it in Boston this year, but it's well beyond "good", as you initially described it. It's well into the top 1% of amateur marathon runners.