I’ve only been doing this for over 10 years.
My 4 plants are about a month into flower. Doing real well, lush, covered in buds. No deficiencies. Already getting frosty.
I prepared 3 gallons of GH Maxibloom and added Beastie Bloomz bloom booster. Mixed well, and allowed it to sit all afternoon to make sure all was dissolve.
After the dinner, fed all my plants, and they I realized. I NEVER PHed!
First time I ever forgot. I’m going to think about it all night.
You could remix same nutes and check ph before adjusting, at least you would know what you gave them. Probably not off enough to hurt anything though.
Is it the same balance you give at each previous feeding? How much adjustment is required with those?
Don’t lose sleep over it, you’ll be fine 
I usually pH my water about an hour after I mix in all my nutes. Like to mix the nutes in luke warm water so they dissolve rapidly.
Usually when I run my pH I come in around 5-5.8.