New tank

[Tmt]

I have a three inch overhang on each side. The glass is not sitting on the stand because it does have a frame. Do I need to get an extension or…?

 

[emeraldking]

It's just a small part that exceeds. And being in a bottom frame, this shouldn't be an issue. At least, if the bottom frame is sturdy enough. But fore sure, it wouldn't harm if you would use a shelf with the right dimensions.

 

[Archerfish]

You need a stand that is properly sized for that tank. The overhang is absolutely unacceptable. Don't use an extension that could flex. You need a solid base that supports the tank's entire perimeter.