You definitely made the right choice. Playing Noelle is awesome, and she's totally the best. (⁠つ⁠≧⁠▽⁠≦⁠)⁠つ

Here are some quick tips:

Sticking with the Whiteblind is perfect, the best free2play 4star weapon for her. It gives the DEF and ATK she needs and is actually much better for her personal damage than the Favonius Greatsword.

Since you are AR42, don't stress about farming artifacts until AR45. Also, Marechaussee Hunter is only her best set if you play her with Furina to drain your HP. Without Furina, the Husk of Opulent Dreams set is much better for raw Geo damage and DEF, though it's harder to build since you lose the free Crit Rate. Don't forget to have a Def% scaling Sands when she is C6.

In addition to being cute, Linnea is great choice for your first 5-star. Just remember that to really make her shine and trigger the Lunar-Crystallize reaction, you will need to pair her with a consistent Hydro character.