183.7 acres out of ne)4 of section 21, block C-30,PSL Sy, Gaines County Texas

I hold an interest in 183.7 acres out of NE/4 of sec 21,block C-30 and am considering a lease proposal of $350 per acre,20% Royalty, 5 year term,with 2 year option. Is this a fair offer? THANK YOU for a reply.