Will I fit in an airplane seat ?

Definitely not comfortably. What airline is it? Hopefully it's a first come, first served seating arrangement and you can get there early. It would be best if people can choose to sit next to you instead of you squeezing in next to them.

Lost some weight you fat cow! 

You have at least four months before you fly. One word: ATKINS.

I will be buying a first class seat and hopping for the best! 🤞🤞🤞

Even if you can cram yourself into a seat and use an extended belt - you are going to make people next to you miserable.  The coach seats are 17 inches wide. You will hang over each side, and will intrude on you neighbors, not only with your butt, but your arm fat  and side-belly fat - you know that is the truth.  Comport class is no better - not wide enough, just more leg room.  So if you can get a First or Business seat - preferably one on a flight that has single seats at the windows - you will not bother others - until the food and beverage cart comes down the aisle.  You also will have SERIOUS problems in the rest room - in all fairness, it is built for gnomes.  Yes, large people do fly - but they suffer, and so do those around them.

Buy 2 or3 adjoining seats.

Trolling score: 3/10