Opinion question: When is one prepared to freelance?

At first you should have a parttime job to cover your living expenses.
If your able to sell 60% of your time you're good. The other 40% you aquire new clients and do the paper work.

When you know you won't lose sleep over shipping poor quality code just because the client had unreasonable requests.

Most clients (bless the remaining few) will approach you for your experience but will pay you to deliver their bad ideas

To be a full-time freelancer requires dedication and time. You have to be known, build trust, and show a great portfolio. And as mentioned before, have some savings it's really important to keep your sanity.

Other than that, you can start freelancing anytime, if you want to do it occasionally. It's useful to build experience or get involved in interesting projects.

When developing an entire simplr app from scratch becomes easy enough that you don't even think about doing it.

Freelancing introduces new complexities such as client marketing, money, taxes, all that stuff. You'll want to focus on those and not spend time thinking about what you're building. It's very hard to learn while freelancing and make money at the same time