The shafts I bought are 31 inches I was told to cut them to my draw length before installing the points

I think it is about 28inches.  will the extra length cause that much difference??

Thanks

It is not about the extra length, it is about the proper spine tension of the arrow from your bow, leave yourself 1/2" for broad-heads, have someone measure while you pull it back. My draw is 32 1/2 ", makes for long ass arrows.

I did mention I was a newbie?  Thanks

Have someone mark the arrow with a pencil/marker 1" in front of the bow when your at full draw. Do this several times to make sure you get an accurate measurement.

The goal is to use the shortest arrow for your draw.

As the arrow becomes shorter, the spline becomes stiffer. The heavier the bow's draw weight, the stiffer the spline needs to be.

A longer arrow requires more feather or tail drag to stabilize it....especially with a broad head. More drag slows the arrow.

Short arrow = smaller diameter, lighter weigh, less fletching = faster flatter flight

All of which is out the window since he already bought arrows of a particular spine, so now it's a matter of matching arrow length, tip and tail weight and bow power. The length will be whatever makes the math work, or cut to "ideal" length for tip position and hope it's not too stiff (assuming they were the right spine shafts and that's not still too soft)

In practice, take them to your shop and ask for help. They'll either run it through the software or open up the catalog and find the chart for those shafts, find out what points you plan to run and your draw weight and figure it all out close enough for practical use.

Op, arrows get trimmed so that with a particular tip weight (and to a lesser extent the weight at the tail) the ACTUAL spine is correct for the energy impulse of the bow. That isn't just a matter of draw weight and length, but they both factor in. It's not a simple formula and most folks struggle with the charts which only give you the specific info the manufacturer decides to give. There is software that does a more complete job. At this stage, tail weight isn't a real factor if you aren't doing anything crazy like six fletching plus a lighted nock with a heavy wrap... If you stick to standard 90, 100 or 125gr tips that's also fairly easy to find or guesstimate on the chart and they often give a "add or subtract x per 10 grams of weight..." kind of info. If you start diving into it you can write multiple doctorate thesis on the subject and people have.

The GOAL in an ideal world is to wind up with an arrow that is just long enough to be safe in your bow in terms of keeping a broadhead clear of your hand, with whatever weight tip and such you choose, and has the right ACTUAL spine (as opposed to what is printed on the arrow). The arrow's rated spine assumes 28" long as the cut length unless they tell you otherwise. Don't get all stressed out about it, in most cases, you just need to be in the right ball park unless you're trying to shoot long distance with precision. At beginner distances? Eh, it's worth being aware of what's involved but not going nuts over. A lot of folks will default to shorter cuts because being a bit stiffer is often considered better than too soft, but unless you're REALLY soft it's not really going to matter for a beginner. By really soft I mean you have a 450 and you need a 300 spine. That will probably effect your results noticeably.