The first week of OCS you're going to do a long-form Flight Physical. Maybe 1/5 people got "NAMI-whammied" when I was there and had to re-designate. The reasons ranged from eyesight to anthro-measurements. Most of the the people who had to re-designate decided to DOR and were home within a few weeks.
If your eyesight holds steady until then, you could pass and be fine. If not, chances are you'd either go SWO or NFO. You'll do another NAMI visit when you check into Pensacola. The only guy I knew who passed the OCS physical and failed in Pcola went NFO. They'll just put you to work at Flight Management until the board meets.
I'd go to an eye doctor a couple times between now and winter and get a thorough check. My eyesight has been on a steady trend downwards for a few years, so if that's how its been for you, it might be worth looking at Lasik if you definitely fall out of range. You're only 20 years old (I'm 28 as an SNA), so you've got plenty of time. It's either that or make the gamble at OCS. It depends on how your eyes are holding up until then.