It's good to work as an associate for a few 1-2 years to gain the experience. However, the longer you depend on your associate job to support yourself and your family, the harder it will be to get out of it. When your associate job gives you a comfortable lifestyle, it's hard to give it up. IMO, it's better to start your own office early in your life. When you are young, healthy and have no kids (or have kids but they are still very small), you are able to devote more of your time and energy to build your practice. There is, however, no guarantee that you'll do better financially when you have your own office. If your practice fails (because you don't have the right business skills to run it), it's better for such failure to occur early in your life. You are still young and you can always go back to work as an associate.
When my GP friends and I started our own offices, we still worked part time for someone else. To give our own offices more days, we had to work on Saturdays and Sundays. As our private offices gained more patients, we slowly cut down our associate days. Eventually, many of my friends quit their associate jobs and worked full time at their own offices. And when many of the debts were paid off, they started to eliminate the Saturday and Sunday office hours.