Now that Eir accepted that she was reincarnated,she plan to make the most of this second life given to her. As this was a world with magic and superpower, as an otaku at heart, she was tempted to gather power and be the strongest. Or maybe enough strong to act as a superhero.
Not that she wanted to go around saving people, she just wanted to be able to put up a fight in tough situations.
As this was the world of MCU, there was also the existence of infinity stones. If she could get her hands on them then wouldn't she become strong enough.
As she have seen most of MCU movies and remembered the locations of infinity stones, she could get her hands on them if she became strong enough to travel around from planet to planet.
It will be quite dangerous and it will attract the unwanted interest of many but as long as she get the power to blow through her problems, she wasn't afraid of them. Kinda cowardice of her but she's wasn't willing to let go of this chance of second life and as a goddess on top of that.
So her plan was simple. First get strong enough so she could wield and use those infinity stones. That shouldn't be a problem as she was born more then a thousand years before the Avengers plot and appearance of all those infinity stones one by one.
She had enough time to learn and get strong. Her first goal was to learn sorcery of asgard. As she was really fascinated by the power Loki had shown in movie. Like creating illusion. Facking death and all that. It wouldn't hurt to have some tricks up her sleeves too.
Next in line will be to learn the sorcery in midgard or earth as she wanted the power to teleport around and she was sure that she could learn how to utilise the power of infinity stones their.
And after that was all done she would go around galaxy to collect those colourful stones.
Perfect plan.
Now she would just have to grow up a little so that she couldn't have to act as little girl and do some serious stuff.
As she was an introvert in her previous life too she kept the act so people didn't bother her much. She was usually in library or in her mother workplace anyways so she didn't get dragged out to play with other children war related games.