I think it’s OK — in the early-ish days.
If you have incredible traction and trajectory, say growing > 15% MoM at $1m in ARR or growing > 25%-30% MoM after $100k in ARR … you are onto something great.
If you can’t quite see $1b at that phase, it’s OK. Most of us, if we are honest, can’t, especially in B2B/SaaS where we lack network effects and a pool of free users to draw on.
You can figure out what you look like as a Unicorn a little later. You’ll know by $4m-$5m in ARR.
But if by then you can’t see it … then I don’t think you’ll achieve it. There are too many people to hire, too many VPs to convince to join, too many jets to get on, too many competitors that will see your progress. And want to take you down.