NTA - your mum’s behaviour, especially the social media posts, is very immature. However much she wants you home, guilt-trippy Instagram posts are not the way to do it.

However I do think that you are being a little short-sighted about this. If the situation in Sweden worsens then it’s very likely that your dance studios will close and you will not be able to see your friends. If they choose to go into lockdown as other countries have done, you will be stuck in your accommodation without seeing your friends just as you would be in Germany, but also without your family. Obviously it’s up to you what you do, but I would not consider “24/7 dance studio access and hanging out with friends” as guaranteed given the current situation.