I consult a pile of methods and sort of average them out.
Most charts, though don't go as young as 14 but two that do are:
People's Choice (average deemed desirable by other 14 year olds near your weight): 103#
Doctor's methods: B.J. Devine (1974) says: 110#
J.D.Robinson (1983) says: 116#
D.R.Miller says: 123#
Average of the 4 says 113# is ideal for a 5'2" 14 year old girl!
(I assume you're not a boy named Ashley


)