Reddit mentions of Cotton Craft - 100% Pure Natural Eco-Friendly Jute - Fully Reversible - 4 Feet Round - Braided Dots Round Area Rug

That layout is probably the most optimal for the space you have. I think putting the bed on the other side of the room would make it feel more choppy because of that indent next to the closet. It would be chunk of space at door/dresser > closet passage > chunk of space at foot of bed. If that makes any sense at all. The shelf thing - So you would have a 2-3 foot gap on that side of your bed to accommodate for that shelf. Is that a walkable, usable space for you? Does it crowd the closet/entry too much if you do that? Can that shelf fit at the end of the bed in the corner by any chance?

So! How to make it a little more grown up - I would suggest starting by updating your bedding. The feminine-industrial-boho-ish vibe you've got started is cool (yes I just made that up), just ramp it up a bit.

I believe you have a comforter? Swap it out for a new one OR get a duvet cover and use your existing comforter as the duvet filler (just make sure it will fill the cover, or just get a duvet insert). If you do a print, stick with a small scale print like the floral you have now, or an abstract muted pattern/texture - a bold medallion or stripes might eat up the "visual space" in there. Then you can do the "fancy people" thing as I call it, and get a coordinating throw for the end of the bed, folded neatly along the foot of the bed.. Look at some staged pictures of bedding you'll see what I mean. Sometimes people get a bed scarf specifically for that but a light weight throw or coverlet works just as well. Bump 2 of your pillows for square euro shams in the back and keep 2 standard pillows in front - and feel free to add in as many or as few decorative pillows as you can handle. If the big euro shams seem like too much then 4 standard pillows like you have is fine just prop the ones in the back up so it looks layered.

Something like this would look nice with blush/pink sheets if you want to stick with the colors you have - plus you already have a pink throw you can use at the foot of the bed. It's a lot of texture but its subtle, then splash more color in your future wall art & plant pots. Maybe your artwork/photos can be framed in natural wood to match your light fixture and/or black to match your bed.

I also see a woven basket hiding - maybe play off that with a round jute rug. Peek that out from under the foot of the bed i.e. if it were divided into 4, have 1/4 of it under the bed and the other 3/4 poking out. However it best fits. You have carpet so it's not like you need a beefy rug just something decorative. Lot of ways to play it!