Getting funded through YCombinator is not a major dependency, nor is moving to San Francisco. There are benefits to both, but they are by no means required.

Don't worry about premature optimization and how you are going to scale your business with or without investors. Build that MVP and see if you're building something worthwhile. If you are and can demonstrate that people are actually interested you shouldn't have a hard time finding someone interested in investing.

The most useful advice I can say is just start. Learn as you go.