I see a 29 minute connection at IAH, not 31 minutes. 29 minutes is under the minimum connection times. While the connection looks doable on paper, I wouldn't recommend it.

If the 11:30am IAH-SLC flight is missed, the next CO flight isn't until 5:35pm. If one is lucky, there are DL flights at 12:15pm and 3:50pm.

I'd recommend getting rebooked to a better connection (e.g. via EWR in the afternoon) or asking for a full refund and rebooking if fares are now lower.