How do I know if I can get a lingual frenectomy?

Ask your dentist. Anyone can get a lingual frenectomy. The more important question is do you need to have a lingual frenectomy?
Get consult. Do you mean if you need a lingual frenectomy? If your tongue lacks mobility and you have a lisp, you may need this done. Visit an oral surgeon or a periodontist for a consult.
You can. You can. The question I have is why now at age 47? Rarely the lingual frenum contributes to the loss of tissue behind the lower front teeth. Most commonly the procedure is performed on children with a "tied tongue" causing a speech impediment.