How many inches can I lose off my waist in 2 months?!

Hey, I'm going to a theme park in 2 months and I'm worried I might not fit in some rides.

I'm 5 ft 7 and weigh a massive 18 stone.

At the start of the year I weighed 19 and started weight watchers which is going brilliantly.

Last time I went to this theme park was about 6 months ago, and I got on everything, but only just with a few of the rides.

How many inches can I lose in 2 months?

I'm doing weight watchers and I walk to and from college (yes, I'm 17, how bad is that...) which is 30 mins each way, and I walk all over my town centre every lunch time, and I do 65 push ups and 65 sit ups per day, so I reckon I do enough exercise. I'm male in case that matters.

Also, I'm going Disneyland Florida in September, so how many more can I lose in that time??

Thank you so much! 10 points to best answer as soon as Y!A lets me!