no. I would never call myself "inżynierka". This is complicated stuff, which is changing very rapidly but many names of traditionally male occupations/positions have only male names and female names feel deregatory/ did not catch/ describe a wife of a man in that position.
inżynierka and magisterka right now are student slang names for Engineer thesis and exam/ Master's thesis and exam
I also wondered whether there would be a female equivalent. It seems the same process of keeping single terms irrespective of gender is going on in both Polish and English. Good thing too!
the process is going in opposite direction. In English you reduce a number of gendered words, in Polish we invent new ones. But it takes time for them to be in general usage. And out feminist movement kind of goes in both directions. On one hand we want the titles to be on the same level, and some are not perceived the same, on the other we really hate undeclinable words, and sometimes it's a grammar nightmare for Poles.
Some of them are quite funny. Recently I have heard the word "gościna" for a female guest. Needless to say about words like "ministra" or "premiera" which were objects of jokes.
"Moja siostra jest inżynierką" was rejected a short while ago. "Inżynierka" is an established word in Polish language, a feminine form of "inżynier". It is made fully in compliance with the norms of Polish language, and it stands on a par with many other similar words denoting feminine forms of occupational names. A lot of people like and enjoy it. (There is a Facebook community called "Inżynierka.pl"). So if anyone dislikes this particular word, it's just that person's personal taste issue, I think. Or, maybe, it's a "new politics" when anything traditional comes under attack from the global generation of snowflakes and other leftist groups - I cannot figure it out. Of course, they have their right to think as freely as they want but why this IDEOLOGY has to be imposed on those who are simply studying languages in their contemporary normative forms? If you are a third-wave feminist activist, alright, just go on revolutionizing the world as you wish BUT do not impose your bias here, PLEASE. By the way, I've found that the Duolingo English-Polish course translates "My sister is an engineer" as ""Moja siostra jest inżynierką.". It is correct, as the word is not outlawed anywhere (and there's no reason it should be).
I think you got it the other way round - it would be more likely for a Polish feminist to root for the gendered word (inżynierka), rather than using "inżynier". While not all women (and not even all feminists) would agree, Polish generally goes towards creating new words for women in a specific profession. Completely the other way than English does. Some of those words enter the language quite easily, some do not. "inżynierka" sounds strange to me and I agree with immery that it usually denotes the engineering thesis. Especially that I did study to be an engineer, and I did observe many of my female friends posting on Facebook about their graduation - I don't think any of them wrote "Jestem inżynierką!!!".
Still... it does not sound too weird to accept, I think. And obviously you're right that it's in compliance with the norms, and that "Inżynierka.pl" example surely helps. Maybe it will gain more popularity soon. OK, added.