Investing in bitcoin requires that you should have a stable source of income that makes provision for discretionary funds after all necessities have been taken care of, anyone without a source of income should not invest in bitcoin untill the they have secured a good source of income, this is because without money you can't invest and you don't just plug money from trees, you need to work for it, some work harder than most depending on the job/business, and your income has to be high enough to yield discretionary funds before you invest, because you should never invest with the money meant for paying tax and footing your bills, and also while investing in bitcoin with your discretionary funds, a percentage of your discretionary funds should be saved up for emergency purposes so you don't end up selling your bitcoin when you run into a financial crisis and are in dire need of money.
There is no need to create an emergency fund before investing. Because if you are not investing, then in my opinion, an emergency fund is of little importance. Invest first and then gradually build an emergency fund. Or if you have the money to create an emergency fund, then immediately create it as soon as you invest. Try to keep 3 times your disposable income in an emergency fund.