Hello Alisa and welcome to this wonderful website
I am from UK and have been 14 months on HRT.
Most of us girls on HRT have their Blood Tests done every 3 months for the first year but if your doctor wishes to take BT earlier, that is fine. However it takes time for any doctor to determine the right dosage of both E & T and that may be the reason why your doctor requested a BT after only one month.
Also as Randy says, it is necessary to take your BT on a consistent basis; there will be a different reading depending how long after taking the medication or applying the patch. I am advised to take BT the next day after applying patch and therefore to wait 24 hours.
I suggest you do not worry but ask your doctor about timing of the BT.
I wish you every success and happiness on your journey.
Hugs
Pamela