Got a full time offer from my part time job is the compensation reasonable?

I have been working with my job at a nonprofit for about 3.5 years. I started as an admin assistant making $15/hr for a little over a year then was promoted to a coordinator position within another department at $25/hr. At the end of last year I finished my undergrad and was given a pay bump to $30 an hour because they couldn’t offer me full time work and benefits at that time. I was just given my full time offer and I’m maybe a little disappointed in the compensation. Here’s the offer- 52k a year, 21 days of pto, health insurance fully covered (I think, some changes have been made there may be a small cost to me). The salary is really my main concern. This is my very first salaried job but when I do the math, this comes up to a lot less than $30 an hour I’m making this year. I expected somewhere closer to 60k. Like I said I’m part time so it’s still a pay bump and I’m thrilled about the insurance, but I’m making less per hour with a lot more obligations. I’m going to accept the offer and I’m grateful to have stable work right now as a new grad, but should I try to negotiate the pay? I found out from another employee that almost everyone in a manager position is making >60k so I don’t think I’ll get much more. Does the free to very inexpensive health insurance compensate for the difference?

TL:DR- I got an offer from my part time job where I make $30 an hour to go to full time with benefits where I will make 52k a year. Is this reasonable compensation even though my hourly pay is technically lower?