Hi,
I wish you the best in this. I recommend joining a gym that offers classes you would enjoy doing and that also push your boundaries. It’s easier to get motivated if you enjoy what you’re doing.
Also, if you can convince a friend to work out with you, you can motivate each other and that will help you stick to your plan longer.
Alternatively, I’d recommend seeing a personal trainer once a week, or every 2 weeks. They can help you set goals and give you support and advice on how to achieve them.

I always work harder if I feel I’m going to let someone else down than if it’s just myself!

goodluck again!