No, not in and of itself, but does she have any money she has control over? That'd be good from her both from a perspective of learning to budget and for feeling grown up and like she can make some of her own choices. I think I was 14 when I was given a clothing allowance; as I was still quite young the agreement was that I'd buy things like jeans, tops, jumpers, and my parents provided the really big expensive things you absolutely can't do without - winter coat, winter boots (medical problems mean my most suitable shoe is the kind of high quality knee high leather boot that you won't find under £100 unless lucky in the sale), waterproofs (cycling 5 miles to school and back). I was fairly sensible about money so I think they were quite confident I wouldn't blow it all on one expensive brand item, but if I had they'd have let me make that mistake.
I also always got some pocket money, which I was supposed to split three ways - a third into my savings, a third into 'holiday savings' (spending money for summer holiday), and a third to do with as I wished, be it blow on sweets or save for something I wanted. Always worked well. My parents were well off and are generous people so they would also give me the occasional tenner as a treat (for example, if I was going into town with my best friend they'd slide some cash into my pocket and tell me to buy both of us ice cream) but that should never be the expectation and you certainly aren't horrible not to.
What made me sensible about money, I think, was that my parents have always been very open about money. They never said 'your dad makes xxx amount per year', but I always knew (at least from when I was old enough to understand it) that we were in a certain income bracket, some people had more, others less; and also they discussed openly (not with me as such, just in my presence) what things cost and how they arranged their money so I learned about mortgages, life insurances, pensions, investments etc. My DP's parents were very hush hush about such things and as a result he is fairly clueless to this day, they're of the opinion that children don't need to know such things, which is fair enough I guess, but they also didn't teach him about handling money in a general way and THAT is bad. He never had any as a child/teenager, so never learned to budget, never learned about financial affairs. He's smart and reasonably sensible so once he was thrown in at the deep end when he moved out he figured out at least the basics and didn't end up in trouble, but I'm still the far more clued up one.
Sorry, bit of an essay. What I'm trying to say is, no, you shouldn't give her more money to make her less horrible, she's 14, I'm sure I was horrible when I was 14 (my mum will probably confirm this :o ) but in a more general sense, it might be good to start thinking about how you want her to deal with and learn about money. You don't have to tell her more than you're comfortable with, but it'd be good to give her some insight into how household finances work, not by sitting her down and showing her, but just by making sure it's talked about, not a taboo subject.