You have taken the first step by making the decision to improve.
My portly self has been there for 25 yrs and I too have made the big decision.
Dont stress, dont add any extra pressure to yourself. You CAN do it, we CAN do it.
I cant give too many tips just yet but heres a couple of things I am implementing.
1. Exercise in the morning
2. Breakfast is the most important meal of the day.. don't skip it
3. Stay OFF the scales except for your weigh in day.
Exercise is something I never did. Now I am aiming for 10.000 steps a day....but I'm not stressed by the numbers.. as a senior I'm entitled to a discount anyway and the experts give a time limit for the steps. Well they can take their clock and keep it.. I'm retired I do nothing to the clock anymore. I started at 2500 steps and I can tell if I'm getting faster.. forget the clock
Breakfast.. whats that , havent eaten it in years but now I see the importance of it I have started to.
Scales.. what scales. I never owned a pair, didn't care either. Now I fight to force myself to stay off them except for weigh in day... no getting discouraged
Hope that helps a bit.