Why not execute your checklist well before initiating a landing pattern? Too many pilots wait until after entering downwind, when it may be already too late for timely response to developments such as a change in surface wind, mechanical failure, HEAVY SINK, or unexpected traffic…
There are numerous reasons for not entering the pattern from higher than standard altitude. First, starting with excess height demands that you alter normal methodology, and can lead to unnecessary difficulties. If you lack inexperience or currency what you need is practice, and entering the pattern unnecessarily high denies an opportunity to reinforce and refine ordinary procedure. Perhaps someone else is in a BLIND SPOT, intending to land and assuming you’re not. If they’re directly below they may never see you, and innocently cut you off. No fooling: I’ve seen this happen twice in one landing! Or another pilot may be soaring nearby, lower but still above pattern height, and trying to stay aloft. By entering too soon you could oblige them to give up and land first, before they otherwise would.
If you’ve arrived lower than standard pattern entry height, flying a full pattern would only squander precious energy and lengthen the period of increased hazard. Instead (being very careful not to interrupt ordinary traffic!) fly to the point where you can intercept standard procedure as high and as soon as possible. The objective is to make a safe landing in a safe place. You and them! Nothing else matters.