As others have said, everyone's journey and rate of loss will be different.
However, to give you an idea of my experience, I have lost 79lbs across 9 months. With the first 60lbs taking 6.5 months to lose. I'd say a loss of 50 - 60lbs in 6 months is certainly doable, I am proof of that. But however much you lose in 6 months, 9 months, a year or whatever - it doesn't matter, you aren't racing against anyone.
Just keep at it and you'll get there eventually

best of luck!