Lots of great diet advice here in this thread! I'll offer a little different advice. I'm a CPT (not that necessarily means I know everything) and this is what I tell folks who are in your kind of situation other than the diet stuff.

As much as it sucks, bust out your camera and take some pictures of yourself. If you're confident enough, have a buddy or family member take the pictures so they come out better. Get a front shot, side shot from each side, and back shot. Bonus points if you can do some fun poses pictures too. It sounds kind of goofy, but at your size you're going to have significant changes but it's going to be difficult to "see" the results since you're looking at yourself all day every day. After a few weeks of getting your diet in check and doing some regular exercise, take more pictures as similar as you can to the first ones. Do a side by side comparison and check out the improvement. This can be very encouraging as it'll show you that you are making progress. If you get stuck or something's not working right, it can help as a reminder as to why you decided to get your stuff under control. Bonus points - Once you're down to the low-mid 200s, imagine how proud you'll be to look at your before pictures and see where you used to be.

The weight scale is going to be a useful tool in helping you evaluate your progress. But - grab a tailor's measuring tape and measure your body parts every couple weeks. Upper arms, Thighs, Neck, Waist, Hips, Chest, Neck... Keep a nice spreadsheet or journal with this stuff. I like to use moles or freckles as a guideline so I know I'm measuring in the exact same spot every time. At your weight/size you should be able to see some changes every few weeks. If you go a few measurements and aren't recording any improvements, then you know you're not doing something right and can re-evaluate your diet and exercise habits.

Good luck amigo! I hope to see you back here in a year with some awesome progress reporting!