Welcome! I've been at it for over 1.5years now and I too started with 18650s and my battery bank is working great! as described by many contributers.
However, now that I've achieved a working system - the life of my battery bank is a larger question. Its not clear exactly but in general LifePo4 cells will have double (or more) the lifespan in terms of the number of cycles.
I keep looking at prices but was just able to buy 1600 cells for $1.27/cell that should yield 260ah@48v (or a bit more). Comparing that to LifePo4 of similar power range and the price is much higher (double/triple from my limited sources) and so I keep opting for lower price, shorter life-span.
I only bring this up so that depending on your sources, $ available, expected battery life for your goals, etc... you might want to look at LifePo4 as well as 18650. Once you make a significant investment in one its difficult to switch over the to the other.