Help!

Hey all, i need some help im not really sure what Nursing to do? i quite fancy doing learning disabilities or mental health but ive been told there are more jobs available if i just stick to adult nursing? Also if i decided to do Mental health and the went back to uni to do adult would i have to do another 3 years at uni? Ive been told if i do adult first i would only have to do another 18months to do mental health? x
Are you done with school or Nclex yet? If you look thru the specialty forums here it talks about different nursing departments. I am finding that experience is the only way to tell what specialty is the right fit.