How do I know if my side freelancing can become my full income?

You have already done the brave part, you started. Now you are standing at the honest question of whether the side work can hold your whole weight. That uncertainty is uncomfortable, but it is also information. It means you are close enough to the edge to see it clearly, which is where good decisions get made. You do not have to guess your way through this. Look at what your freelancing earns in a steady month, not your best one. Look at whether the work is growing, flat, or shrinking. Look at how much runway you have if income dips for a while. The answer is usually written in these numbers, not in your nerves. Fear says leap or stay frozen; the numbers say something calmer and more useful. Spend one evening this week adding up your real freelance income over the last few months and what you would need to cover your life. You are not deciding today. You are gathering the facts that will let you decide without panic when the time comes.