The most important thing is to start consistently, not the amount of Bitcoin. To start any investment, you should first have money, sufficient knowledge, or absolutely perfect market conditions.
You don't need to understand everything about Bitcoin before you invest in Bitcoin, and you don't need to start your investment in absolutely perfect market conditions because Bitcoin is highly volatile, and you don't know when the market will be favourable for you to start your Bitcoin investment. If you have a source of income that guarantees you discretionary income, you can adopt the DCA strategy and start your bitcoin investment weekly or monthly based on the one that is convenient for you, and you need to set aside your backup funds or emergency funds. In case you have any emergency you didn't plan for, you can depend on your backup funds or emergency funds to solve your emergency, and it will not influence you to sell your bitcoin.