it will definitely be fun, both being a student + working on your own project.

From my experience, for some reason PhD advisors tend to work well/really like mature students. No hard data on this, just an empirical observation across 3-4 labs I've worked in before I left academia.

With regards to career prospects (outside academia ofc), you definitely gain respect but anything more than that largely depends on your area of research. Which one is it, if I may ask?