You're assuming the degradation is linear. I don't know that this is the case. (*)
If you got it on Feb 9th then you have well over nine months left on the original warranty. I truly wouldn't worry about the matter until near the end of the warranty period or until it actually starts to impact your ability to use the system.
You may want to do a
battery recalibration if you haven't done so, but otherwise I wouldn't be borrowing trouble from tomorrow.
(*) Maybe it is, maybe it isn't, more I'm pointing out the assumption rather than saying it's right or wrong.