Missed OG.. by alot

So I just finished my 3rd brew.. it was a wheat extract kit with specialty grains and LME. The OG was supposed to be 1.051 but when I took the reading it was 1.058.. almost 1.060. I have never (in my previous 2 brews) missed my OG by that much. That is alot. I followed instructions to a tee.

What may have caused me to be off on my OG by that much and will it affect my beer in any negative ways?

What was your recipe? Boil volume? Final volume?

temp and humidity can effect boil off raising OG numbers. RHAHB.

If you did a partial boil or had to top off at all to get your 5 gallons, your mix water may not have been well mixed.

+1, If you did a partial boil then the top off water wasn't mixed enough, just go with the OG that came with the kit. You may want to get yourself a Mix-Stir, run that bad boy for around 5 minutes after you throw your wort in to the carboy, it'll mix everything up really well and aerate your wort before pitching all at once.

You got a little extra from the grains, or the LME gave more than the recipe expected (LME is not as standardized as DME), or you boiled longer or harder than the recipe anticipated. Or a little of all of them. If you have 5 gal. at 1.060, then you could have added 3 qts-1 gal. of water to get it to 1.051. Not sure if you had that amount of room in your fermenter. Either way, it will be fine, 1.060 is not that far from 1.051, just a little more alcohol in the end.