Don't have to convince me.
I will say that if you start out, really enjoy it and plan to do more of it, a good bike -- Trek, Giant, Cannondale, Specialized -- is well worth the investment. Buy from your local bike shop and get one fitted for your body geometry. It makes all the difference in the world. The women specific designs are great for females, and if you're short or tall, typical bikes you find at big box stores won't be comfortable.
If you maintain your bike, they are built to last years -- both of mine are about 10 years old and I've only done maintenance items like chains and tires and tuneups -- and will be the most comfortable ride ever, meaning you'll ride even more. I know they are expensive, but if you prorate it over years of riding enjoyment, it makes sense.