Welcome. All good advice above. My reentry into cycling after a 14 year layoff and the need to drop much weight is similar to yours.

My only advice is take things slow with the weight loss and cycling. These things take time and going too fast is the best way to kill the whole process. I started with a Mt. bike on the rail to trail until I could do 1/2 hour of cycling. Forget about mileage as a sign of progress, time on the bike is what to monitor. Also if your diet does not change you can ride till the cows come home an the weight will not come off. Good luck.