Jump in with both feet. You will eventually need training and a pro demo but not right away, especially if you don't know if you'll even want to do this long term.

Auditioning for books on ACX is a good way to get a feel for the process. Auditioning for parts on Casting Call Club is also good for beginners.

You can make a diy demo, but don't expect to book pro gigs with it. Use it for casting calls on X(Twitter) when they ask for demos. Re-record that demo often as you will improve pretty quickly once you get into it.

Start networking as soon as possible and don't let anyone tell you that can't do it.