Bilateral renal cortical thinning and hypertension, need for panic?

Hello I am new to this forum. I'm a 30 year old female with quite a healthy lifestyle and no known history of issues related to kidneys, apart from a few years with frequent UTI's in the past. I have moderate hypertension for which I am undergoing a variety of tests, and an ultrasound showed renal cortical thinning (between 8,8 mm and 11 mm) of both kidneys. about 10 years ago an ultrasound also indicated renal cortical thinning, though I don't know how thin they were exactly, but my doctor didn't insist I follow up. I am afraid that by not following up the situation may have deteriorated. I am now waiting for the results of blood & urine work, but will only have the results in about a month and I am really stressing out about this. I haven't been able to find out what normal renal cortex thickness is, so I don't know if the thinning of my cortex would be considered mild or severe. Could someone please tell me what is considered normal cortex thickness? I of course don't know the underlying cause yet, but could my situation mean I might one day need a kidney transplant or dialysis or am I panicking about nothing?