Hmmm... I teach that age and some of the things I hear from sensible 14 year olds make even me feel shocked.
Sorry. Couldn't resist. I think (but am not sure) that 14 is way past the age to legally be left alone for periods of time and it used to be fine to babysit from around 12 (but is probably 16 or 14 now a-days). I certainly used to babysit for others when I was 14... however when my parents went out they'd still get a babysitter (I have a brother 3 years younger and a sister much, much younger) so there is another conflicting message for you.
As will probably be repeated over and over on here she is your daughter and you know her better than any of us. In this age of communication you don't have to panic about looking up the payphone number for just outside the restaurant along with the restaurant's number just in case and leave 20 other similar numbers with her and then panic about what will happen when you are travelling.
If she is sensible, knows what to do, isn't being expected to cook while you are out (although we used to do that without issue when we were 14) and keeps the doors locked then... but I look at my 10 year old boy who is ultra sensible and worry. Ah he'd be fine when he is older. Worst we'd find is he'd still be on the Wii when we got home and he'd just say "oh, sorry, I didn't have my watch on".
um... I'll shut up now. That probably hasn't helped.
You sure about the lack of boyfriend?
I'll shut up. Shutting up.