I’m going to be 100% honest in the post.
If you keep it, you might be able to grow it but it’s not garenteed
If you sell it, there’s the risk of getting scammed. 600$ is a lot of money, and there’s a scam going around where the person either makes you go first, pays half and when you send the account leaves, or charges back.
I personally would grow it, but if you do want to sell it, you need to make sure you do it right
I realize there is a lot of problem when trying to sell accounts
You could also try and list it somewhere like Socialtradia / fameswap see what kind of offers you get? That way at least you’re protected.
I listed it on fameswap
Yeah worth a shot, I’ve never actually used Fameswap only Socialtradia be interested what you get for that acct so keep us updated 
am a noob but in my IMO i have come to discover if someone is offering you a lot for something you have, lets say your page now $600 for a 16k page it means in a month you can make a whole lot more from that page, might take a while but just gotta find how grow the brand bigger sometimes a Name is better. These days what makes people money is the brand Name
just my IMO tho