Age in no way is a deterrant for a Masters, but you might expect a question from the VO like “Why now”. As long as you can justify your answer I don’t think visa should be a problem. You might also want to address that question in your SOP’s to stand a better chance of admits.
I am answering some of the older questions on the forum here so people can get much needed help. If you have a degree and a job in home country for many years, it is perfectly alright to try for career growth by advancing your education. USA is one of the few countries in the world where age discrimination is illegal. Whether you are 22 or 92, and you wish to study further, go for it.
All the best
Dr. Sandeep Shankar, Colorado Heights University, Denver, CO 80223, USA. www.chu.edu; firstname.lastname@example.org