Sudden change in behaviour. Puberty?

Hi everyone! Could you help me with some challenges I’m having with my little dachshund who just turned 1 year old?

Here’s the context: we got this female when she was 8 months old. Before that she lived on a farm with other dachshunds, but she withdrew a lot, so it was better for her to be placed with people.

Because she didn’t receive any training, it was difficult at first to raise her properly, but after a while things went really well! She’s house-trained, sleeps through the night on her own in the living room, and she’s very good at being alone.

Unfortunately, we’ve noticed that in the past few weeks she’s been showing different behavior. She suddenly starts barking at night; we’ve put her in the hallway and that helps, but we would really prefer to have her sleep in the living room. Letting her bark and ignoring it isn’t an option, because I live in an apartment building. I’ve also noticed that she starts barking when she’s home alone, and she gets extremely excited when I come home. I can clearly tell that she hasn’t been resting calmly in her bed. Other than that, she eats and drinks well, she’s active and enthusiastic, and she doesn’t seem to be in any pain.

Does anyone have any idea where this sudden change might be coming from and what I can do about it?