I am a manager at a store...?

I am a recent college grade, and I landed a job with a great company as a manager. I have been With he company for about 3 months. I am in charge of about 45 employees including two supervisors. One of the supervisors has worked there for about 12 years. I am only 23 and now I am in charge of 40 year old supervisors who has worked there for 12 years. She does not like me because she says that I don't communicate things to her, but I always send her recap emails, ask her how things are going etc.. As a manger I am entitled to make decisions, and if I make one with out her consent she gets all pissy and moody. How do I deal with her? should I just go to her for ever thing since I am still brand new? is she jealous? how can I better my relationship. BTW she has no college education, she is loud, and always has something to complain about.