The last time I skated (roller or ice) was about 10 years ago and I was like 70 lbs lighter. I was able to roller skate fairly well, basically the same that I have my whole life. However I never took the opportunity to go again and now I would be afraid to because of my weight and falling.
I went ice skating around that same time and I was not able to do it at all, I could not balance myself on the blade. This was suprising, because I have always been able to ice skate very well, so my weight must have had something to do with it.
But...You should try it...IMO, if you are heavy, but have good balance to begin with, I think that you will be able to skate. I don't have good balance anymore, so that in addition to my weight scares the heck out of me...so I will be keeping my feet in shoes, thank you very much!
Good luck and let me know how it goes...I'll be cheering for you