Hey!! It's another first bike question!!

Great idea to get a bike! Check out the Honda CRF250X and KTM 250xcf is are cool bikes. A bunch them on Craigslist.

Yamaha came out with a cool bike, the YZ250FX.

All those bikes will be great for your size and ability, also give you room to progress.

Goodluck and have fun!

Pick up a mountain bike to lose weight, the skills help you with motocross as well.
For a bike... yes the 150F is way. Way too small. That's a kids beginner bike. I can't believe they even rented that to you.
Like the above poster I suggest you pick up a KTM 250XCFW, Honda CRF250X, or any of the other 250F Enduro bikes. You need something tame but not a kids bike...

I would recommend around a 05 YZ 250. It will be great to learn on and enjoy for years to come.

BRO, if you have the income to buy a bike, a place to ride, and the desire to achieve a goal. All your missing is the bike.
IMO any 250 two or four stroke would be right for you.