At one point I weighed 220 pounds at about 5'-9" or 5'-10". But I got down to 160 with diet and exercise, gained back 15 pounds of muscle, and I've kept the weight off for 3 years now.
So with that in mind, as a side note, be sure to go nuts with a healthy diet, otherwise exercising will be much harder, and much less rewarding. I studied nutrition for about a year prior to making a lifestyle change. It isn't one of those things you can really jump into with no background knowledge. It's a good way to get sick.
Not that I'm implying you don't know anything about nutrition, or that you aren't already eating well, because obviously I don't know you, but just sayin' in general.
And about your original question about weight, even someone who weighs more than you can often get away with using high pressure kevlar road bike tires pumped up to capacity. Some of the fattest road riders I've met have to do this, or they keep having pinch flats. But you're probably not heavy enough for that to apply, so don't worry about it.