>>339126606
Can you afford an Index and do you spend too much time in VR? If so probably, but the controllers are going to be a downgrade to your Rift S and the panels aren't as good.
If you already have a Rift S and already linked your Facebook account then there is nothing stopping you from getting a Quest 2. It's a pretty good headset for what it is and wireless is nice (for some games). 
t. owned a Rift S and now has Index and Q2