One never knows. We have had our room ready by noon and as late as after 4pm. My suggestion is that even though you might/might not get a text, if you happen to be around the resort, check at the desk. Plenty of times we were told our room was ready.
Our trip a few weeks ago we did not receive a text saying, "your room is not ready" (or whatever they text). We arrived at the resort later than the check-in time I put in on line (earlier than the 4pm check-in time). I thought it was odd so I went to the desk. We lucked out, our room was ready.
If we are exhausted and don't go to a park or DS, we hang around the resort or pool (we pack a bathing suit). I will check at the desk maybe once if we have not received a text by 3pm or so. I know we need a little patience. Don't want to bug them constantly. Good luck!