As an adult, you’ve navigated the NT world more or less successfully to date. Obtaining a diagnosis (or going through the process and being told that you’re NOT autistic) is something you will do for yourself to ease any concerns that you may have, and perhaps gain a greater insight into any difficulties you experience*.
You are not required to get a diagnosis. You may decide that you’ve coped till now, and that a diagnosis will not alter anything in your life**.
You do not need to divulge your diagnosis to anyone other than the professionals involved in getting diagnosed. They are prohibited from divulging your diagnosis to anyone, unless you consent – so, for example, there’s zero possibility that your employer will find out***.
*: Note, however, that you can read up on autism – I recommend Temple Grandin – and, with a little critical analysis and introspection, you can get much of the information that a diagnosis would give you. That’s assuming you want to deal with your difficulties, rather than get the autism badge.
**: As you’ve coped till now, you will probably not have a basis for obtaining disability benefits. You may be entitled to some supports, such as social skills training. A good, detailed diagnosis may highlight issues that you need to be careful about (e.g., forgetfulness), which may help you avoid problems (by for example, establishing a routine with calendars, diaries, reminders, etc.).
***: I have a nasty feeling that a diagnosis might count as a pre-existing condition in the US, vis a vis health insurance. However, if you have an illness has nothing to do with autism, your insurance would have no reason not to cover your healthcare. Some illnesses, e.g., depression, could be argued to be caused by your “pre-existing” autism, but a broken leg, cancer, pneumonia, etc., not so much.