He's 10 do a fun print

Curtains have no gender. Seriously.

https://www.wayfair.com/decor-pillows/pdp/beachcrest-home-indoor-cordless-blackout-roman-shade-bcmh1420.html

Comes in Blue also.

I agree; many men/males live in houses and have bedrooms with curtains

I actually meant that curtains would be long, so he would probably run into them while playing maybe feminine is not the rigt word

Any color help?

Fun pattern to liven things up... I would skip the valance. You could select a white & navy or navy & gray fabric. I love this source for fabric & custom romans- tonicliving.com. GL!

Color Zen, if I skip the valence will the exterior mount shade look awkward?

Actually, Pottery Barn has a cordless navy roman blind. The color could match his comforter, there are lots of dimension options and has 75% linen. Skip valence.

https://www.potterybarn.com/m/products/custom-emery-cordless-roman-shade-navy/?cm_sp=reducedpip--default--fulldetails

Found these on Etsy and thought he might like

https://www.etsy.com/listing/181210467/airplanes-set-of-4-8x10-cream-navy?ga_order=most_relevant&ga_search_type=all&ga_view_type=gallery&ga_search_query=navy+and+cream+posters&ref=sr_gallery-1-8&organic_search_click=1

I would love to get the PB one and make life easy but it’s too small for my window which is 4ft wide and with external mount I need it to be at least 52 inch.

Maureen, would not having a valence make it look incomplete since there is no window trim?

Sample of window without a trim. I think it looks fine. Imagine a valance on top of this, I think it would feel too heavy.

Once you decide on a specific color, looking for linen, a blackout liner, 54 inches, wide, you might need it custom made. I found this site was informative and looks like they do custom.

https://www.blinds.com/blog/should-i-install-my-blinds-as-an-inside-or-outside-mount