3 months is a bit too long for a pre-order, especially for an asic with a brand new algo, no asic is out yet, and no one can be sure those will be out on time with the advertised specs. here's an interesting read about it:

https://www.grin-forum.org/t/rip-grin-mining-weak-outlook-for-c32-hardware/4996

Oh and GRIN is a well known coin