What is the standard height of a frameless shower door handle?
Standard knob and lever heights for interior doors is 36" above finished floor, If the handle for your shower is 35" from the bottom of the shower door, and there is a curb under the door, that would put the handle about 39-42" above the bathroom floor. Already is higher than standard.

No there is no set rule for handle heights of shower doors that I know of. They are usually set in the center of the panel, which should be about where yours is if the door is the standard 6' height for frameless doors. This is based on observations while shower doors are being measured for by the installers over the years. Nothing was ever specified for the height, just handle style.