Another lane etiquette question-- butterfly in shared lane

Hi guys-- tell me if what I did is fine or being a jerk, please. I just learned butterfly a month ago, and I like to do some (like 8 50s that are fly/back-- I don't feel ready for 50s of pure fly) every time I get in the pool because I REALLY need to build that strength. I'm a second season Masters swimmer, and I want to be able to do the 100 IM at next year's state championships.

So I had a lady get into my lane right before I was about to do this (an older lady who is about half my speed-- I'm NOT saying I'm fast, just explaining how this worked), and what I figured out I could do... bc my arm span is 6'1", so I need the whole lane for fly... is I would wait until right before (maybe two strokes for her) she got to the wall where I was waiting and then I would push off... slightly under her bc I needed to push off diagonally to get into the center of the lane, and then I would do my butterfly in the center of the lane, backstroke on my side of the lane back to the starting wall. When I got back to the wall, she would be just about to approach the far wall, so I would have the time it took her to do one lap back to me before doing the same thing.

The lady didn't react in any way, though she did move over when a lane freed up. There was a lady in the next lane saying I swam like a pro swimmer (I do not... I'm a woman in my 40s who never swam competitively before last September) and that the way I swim I need the whole pool to myself. Then she said it again about me to someone else, so I think it was her passive-aggressive way of complaining that I was practicing butterfly.