Too Old to Be Diagnosed???

My cousin is nearly 50. She has not been formally assessed or diagnosed with autism but has exhibited many classic signs all throughout her life.

Until very recently she lived a protected life with her Mum, and we all simply made allowances for her tendencies. We call it walking on eggshells. She had a terrible time in school and was tested for all sorts of learning disabilities but was never tested for autism. Very frustrating. Now it has become the elephant in the room; it is like we all "think" she is autistic, albeit high functioning, but no-one dare broach it with her directly for fear of really upsetting her.

Last week her Mum died unexpectedly. The family home will be sold, and her siblings will help her find her own flat. This is all going to be so traumatic for her. She will need financial help through PIP as the family is not wealthy, but to do so, she will need to be assessed or diagnosed. 

My question is this: After years of never having discussed with her the possibility of being autistic, HOW on earth do we go about doing it now? SHOULD we even consider it? Now that she is an adult, CAN we? In hindsight, it is something that should have been done years ago and would most likely have helped her. I know she feels different and is easily upset but we have all tried to support her in the wrong way, by pretending there was not a reason for how she felt.

All suggestions gratefully received.