Great jeans for spring and summer!
For tops - how about a striped sailor top in red/white. Bright colors like lime green, coral, rich rose. Strong tones can contrast nicely with the lighter jeans. Maybe not autumnal colors or pale tones. These are still jeans despite the fading, so they can act as a "neutral" like regular jeans, just with a more summery vibe. Navy, as you mentioned, and white (doesn't have to match the tone in the jeans). A bold print that you like, but not a tie-dyeish print.
Shoes? White or bright sneakers. Sandals of course. Again, you could go with bright colors! Not a fan of peep toe boots myself, but they would work if you like them. All kinds of shoes seem to work with jeans, to me.
These are totally fine for any age!