If I can ride alone most of the time, you can too! Just make sure you are prepared. Learn how to change a flat, because sooner or later you will lose your flat-tire virginity and have to do it. Practice at home where you aren't under any pressure. And trust me, it will almost always be the back tire, which means you need to know how to get the wheel off and back on again. I don't have any advice for the long fingernails!
I have a trunk rack on my bike to carry everything I can think of, just in case. I carry a cell phone, snacks, a pump, a new tube, a patch kit (in case I have two flats on the same ride), a small tool pack, a rag, some minor first aid stuff, Tylenol, a health insurance card. I have thought about getting pepper spray or the like because some of the bike trails are pretty isolated, but I haven't done it yet.
Make the best preparations you can and then go out and enjoy your ride! Most cyclists are pretty nice and there will usually be an offer of help if you get stuck, but you don't want to look like a helpless female; It's way cooler to just wave them on with a "I'm fine; thanks for the offer." Good luck!!