Joanna was born in Poland - to a struggling middle-class family, around Christmas, a sign which her father says is because God was watching over them - and why he worked so much harder from henceforth, even if he worked a shitty job. She was dubbed and blessed a Catholic shortly after her birth, due to her father no doubt, but he dubbed all of his children as Catholics from the very moment they were born. Her father was born into a large, Catholic/Protestant (coming from her grandmothers side of the family, seeing as though they were Russian) family and wanted his children to be blessed under his god, and so he did - he named Joanna after Jeana (or Joan, according to modern English spelling of names) of Arc because he wanted his elder daughter to be strong, in any case.
Her childhood was chaotic, seeing as though she had three other little siblings to take care of whilst her parents were at work, which meant that she had to basically be a second mother to them whilst their parents worked twenty four seven to basically insure that they lived in their current home. It lead her to do several magical things, like breaking lamps out of sheer anger at her siblings, or things like that. It wasn't rare to see her being so angry that the poach would burn, and the neighbors would call the police - things like that weren't too rare to see in Joanna's case, for stress makes people act out every once in awhile, honestly, and Joanna was a magical child, so it was even more brutal in her case, unfortunately. Her real first case of magic is her literally burning lamps, quite literally, when her younger brother was goating her on, most unfortunately, and she was nine years old at the time of said incident.
All in all, when their parents were around, life was better (not by much) , her father often times brought back Warsaw Vodka sometimes and drank himself to sleep when things got rough at work. Her mother was almost never seen, because she worked personally under the Prime Minister of Poland's direction, but when she did come home, she too looked drained. But at least she acted like a mother, and wasn't like her father, of whom she had been semi-distant towards throughout Joanna's childhood.
When she got her letter to Dumstrang, she was quite thrilled - it was a path away from her chaotic, shifty family, and she couldn't wait to go there. Her life at Dumstrang isn't important, but it's worth noting, that during that time, Joanna was more relaxed, to say the least. Relaxed from the storm that awaited her at home, whenever she went during the summer and holidays.
Dumstrang, well, it was quite the experience - Joanna had never been popular there to begin with, being highly introverted and not to mention studious, she only had a small group of friends (but a large group of cousins from her father's siblings, many of which were Russian in descendy, considering Joanna's grandmother had been a Russian woman) and kept mostly to herself, for the most part. Being social was never a huge part of Joanna's story actually, but nevertheless, she did, and she still keeps in contact with them since leaving Dumstrang.
As for her arriving in Hogwarts, well, her father had gotten a deal from the English Prime Minister that he simply couldn't resist; being one of the Polish Ambassdors to England (a honor which he rightly couldn't ignore anyhow). He packed his family off immediately at the opportunity and left Poland after a heartfelt goodbye to his extended Polish family (which includes of his siblings that still lived in Poland instead of Russia, and all nephews/nieces they had) and off they went to Hogwarts, forgoing Dumstrang, to Joanna's infinite joy and happiness, for Dumstrang was known for it's Dark Arts and Joanna's father had promptly made sure that she was wary of Dark Arts, for he himself had no love of it.
Was her father aware of the political crisis in England when he made this decision? No. Likely not. They didn't use the internet and were likely catch unaware of what happened there - something Joanna says so, she doesn't support the Prime Minister's choices, but her father has a job to do for him and needs the money desperately in order to stay in England, so he doesn't say anything against him (at least publicly, publicly he had to show that he agreed with the Prime Minister). Jobs AND not to mention the undeniable risk of being deported back to Poland in disgrace, was on the line for her poor father if he showed insubordination and it unfortunately had an impact on poor Joanna's father.
She, for one, hopes that nobody will judge her nor her family for their decision for working with the current ministry, but she knows that others will not be so happy about it if they heard about that little detail, but being deported is a big deal though. So, she and her family has to make do with it, but she wants to go to Hogwarts, wants to explore it's large halls, and be happy - after all, Hogwarts will be a chance for a new start, for her and her siblings, in any case. Or at least she hopes so, and she also wants to explore the grand halls of Hogwarts, of which she's heard about, even from Dumstrang. She hopes it's good as the plebs in her school say it is, anyhow.