The best time to start accumulating Bitcoin shouldn't just be anytime as you have mentioned meanwhile the best time to accumulate Bitcoin is when you have your discretionary income available anytime doesn't sounds good to me anytime can be no time or anytime can be next 2 years or more if you can figure out what is your discretionary income you can start accumulate as little as you can or as much as you can gradually using the DCA strategy weekly or monthly consistently and persistently and hodl for long time.
You can also say when you have they little you can afford to invest with steadily without any pressure until your income level up, the truth is that source of income matters in Bitcoin investment but we must not start big atleast what matters is a steady source that we can be using to do our DCA without any break, to me in have learnt many things being part of this investment, is have learnt to be conservative, we talking about the future not the immediate stuffs and for us to grow financial in the future we have to be very futuristic financial and that has to do with discipline although I might have deviated but that's what came to my mind, mate you got all right.
Income source is important for Bitcoin investment but more important is discretionary income. You have a reliable source of income but if you don't have discretionary income at the end of the week then that source of income can be worthless. Many folk don't have a stable source of income they have an unstable source of income but have some discretionary income at the end of the week and can accumulate Bitcoin from it and I think it's more potential. Over time they have the intention to increase their Bitcoin accumulation and in the future when a stable source of income is created they can more Bitcoin. It is true that it is not important for us to start big but it is important to start with discretionary income initially. Long term Bitcoin thinking teaches us discipline and patience that is more important in increasing holdings and even which is a much better way than risky trading ideas.