No rule that I know of. And honestly, you can't really judge the end post anyway. Just keep putting one foot in front of the other and you'll wind up where you're going.
How to start? That's up to you. What would you like to get out of this world? You may want to start by joining a gym - you've mentioned your weight many times. But you could also start up some hobbies. I'd recommend an activity where you are out being social but there's also an activity happening so you can feel comfortable. Why might you enjoy? Maybe search through meetup.com?
