How much weight can I loose?

[BiigEv]

Hi, heres a little background information- I am currently 17, about to be 18. I have always been heavy and I was fat until about 9th grade. I have decent muscular definition and am very strong for a teen ( according to all my coaches) . A month ago my maxes were 405 on bench, 585. pound squat and 625lb dL. I have always been a bigger dude and right now I am currently 6'3 and somewhere in the range of 270-260lbs ( don't have scale).

I started dieting around a month ago and plan to keep going. I am losing some strength but at this point in my life that is not a problem. I currently am eating around 900-1200 calories a day and working out 4-5 days a week. I have been extremely strict and have not cheated at all. If i continue this for the next 5 months how much weight could i potentially lose? I am starting to run more often and do other cardio activities as well.

I am hoping to drop down to 220 even if it takes a year.

Also my age is not right on this account.