Hey there mate, im the same 231lb n same age/height as you.
I go to the
gym 3x a week, trust me its alot better at the
gym if you have a friend to go with you.
I see this kid has just joined the
gym I go to, hes short and really
fat, looks about 14-15. His mom drops him off and he just sits around on the machines that you can sit on, e.g the ones to work your legs, and does the lowest weight. Basically hes just being a lazy git.
When you go, do a few stretches in the changing room, go in there, jump on an excercise bike or
treadmill for 10min to get everything warmed up.
Heres what I do with
weights, which is good btw mate.
On any weight machine, start with a very low weight and do 10. Then put the weight up a notch or two and do 10. Then up a notch or two again and do 8. Then finally up a notch or two again and do only 6. After this, if you want, 'pump out'. This means put a low weight on and do as many as you can till your arms hurt. I do it.
10, 10, 8, 6.
Do that for 2-3 weeks, then to save going stale...start doing 10, 8, 6 and pump out, just generally mix it around a bit you know.
It works mate, its like a pyramid.