Have you compared the offer to the royalty payments you have gotten, if any? Also, need to see if you own more “gross” acres, which raises the issue of whether they might be able to drill more wells. The area is also a “stacked” play, meaning they may be able to drill multiple wells in the future at different depths.
In short, the general wisdom is don’t sell minerals unless you need the money, or need to diversify your assets. If you have to sell, see if you can only sell the royalty in this one well and keep the minerals on future wells.