
Lara M. answered 01/03/23
Certified teacher specializing in students with special needs
She was thirty-three is not a fragment. It has a subject (she) and a verb (was), which makes it a complete sentence. You do not necessarily need to add years old, as it is understood that this is what thirty-three is referring to. I would probably add it, though, especially if this is for academic writing.
However, I would suggest combining the sentences to add a bit of variety to your writing. For example: She died in 2002 at thirty-three years old. This helps avoid the choppiness of very short sentences.