Should not be an issue. We've done it a couple of times and are thinking of doing it again in September. A few things that could settle your mind a bit.
I'm not familiar with which airlines have the most flights between these two destinations, but consider choosing that airline. If they have several flights then they will also have several options to get you there should there be a problem with the first flight. For example, I just looked at Southwest Airlines from Pittsburgh to Orlando and they have two flights that arrive before noon.
Try and choose the first flight out to Orlando. You may have already done that. These are least likely to have problem with equipment and crew since there is plenty of time for the aircraft to arrive from wherever it is coming from the night before.
Make sure you book a non-stop, but you've probably already done that.
I travel a fair amount. About 50,000 miles a year by air last year. Flight delays of more than an hour can happen, but are really pretty rare. Flight cancellations are even more rare and unless you are traveling during the winter months, even more rare.
That said, please do yourself a favor and just relax. Be emotionally prepared for the fact that something out of your control could go wrong. If it does, having a calm head will get you through it. We've all seen the horror stories of panic stricken and stressed out people yelling at airline staff and airport security. It just slows them down.