I guess it depends on what your cycle is usually like. If they are typically 80+ days without intervention I don't see any harm in taking it before 60. However if this is just a wonky cycle, you might want to wait the 11 more days just to see.
I realize my story is probably not super common, but I was seeing an RE and she wanted to see if upping my metformin would make me O ( I wasn't Oing at all on my own). I went to see her around CD28 and she said if I don't get my period in three more days, call for provera (yes it was well before 60, but like I said I never O'd on my own so if I didn't O by then by upping my meds, chances were I wasn't going to).
The day I called for provera, I decided for whatever reason to take an OPK. I did, it was positive, I O'd on CD34 and got pregnant. Obviously you can't wait for forever to see if you'll O and I think it was a miracle that I caught it right before taking provera, but like I said you could still O if this is just a wonky cycle...just my two cents.