What color should I paint my walls

Yellow, not too bright, will liven up your room.

Golden

Try to take a picture of the furniture and check color samples at the paint store. That can give you an idea of the color for your wall. If in doubt you could ask some friends what they think.

I am not sure what"forest" is could be green or brown. I would go to the paint store and get some colorful samples and take them home to see what they look like in your lighting and go from there. New trends run around a brighter red-ish brown but it would brighten up the room also it sounds like some of the new yellow-ish colors would give you a brighter and happier feel. If that is too "out there" for you white is always an option then bring in your modern colors with your throw pillows and wall hangings.

Maybe a soft green..... https://www.sherwin-williams.com/homeowners/color/find-and-explore-colors/paint-colors-by-family#/color/6464 just click on the boxes to explore the colors

If by forest color you mean green with brown carpet, a sky blue color may look nice in your room without being too dark

I would go with a soft yellow, a goldenrod, or a lighter brown.

Vicky my house was built in 1905 and we have literally 100's of pictures hung in our house. I just use picture hooks. However we found this clock at our swap shop and it weighed 40 lbs so we took greater care. Got some plate like things that fastened to the wall in several places. We did not want the clock to break. We actually have never had any broken plaster from our many, many wall hangings.

oops, this was answered in wrong place.

Go to a paint store and get a lot of sample cards in colors you like. When you get home look at them again in your room. Tape the ones you still like on the wall. Go into that room at different times of the day and take notice of the cards. Also go in there on days with different kinds of weather (sunny, overcast, stormy). Remove the cards as you rule them out. When you have a couple of cards left, get sample pints and paint a section of wall. And check them the same way you did the cards.

It sounds like a light green or aqua would be a place to start. Even a light grey or tan would probably work.