I believe in the lean startup philosophy, but our love of pivots has a downside, in the belief that it doesn't matter where you start.
Where you start matters. The path you choose matters.
It's never too late to change (until you run out of money), but it gets harder and harder the further along you get.
If you launch a product, it's hard to kill it.
If you take money from customers, it's hard to give that money back...and even if you do, people still won't be happy.
Momentum works for good and ill.
Choose your path wisely.