A great first foray into writing for choir! A couple of thoughts if you want to develop this further:
1. Your soprano part goes too high. You really only want to write notes that high if you are composing a commission for a particular super-soprano soloist who you know can hit those notes and do it gracefully. For the average choir, writing to around a G above the staff for sopranos is about right. If you add a second soprano line in that section, so the lower-voiced sops have something lower to sing, you can stretch the upper part a little. (But not this much!) Another option is to add an accompanying instrumental part and give those upper notes to the player. You could write a piano accompaniment, or add a solo instrument like violin or flute.
2. Find a text! Choral singing is about poetry and the beauty of what is being said, as well as the beauty of how it is said. The only time you hear a choral sound without a real text is movie soundtracks. (It's fine if that's what you want to do, too, but then you'll want to specify if people are singing "ooh" or "aah" or some other filler syllable). Part of the challenge of writing for choir is fitting the notes to the text or the text to the notes well, so if you are working on writing for choir, think about working on that skill as well.
3. Finding your text will help you figure out how to split those long notes up with logical places to breathe. You may want to make a whole note into two half notes on repeated pitches, with each note belonging to a different syllable of text, or remove a tie and do the same thing. Try singing your way through and feel where you want to breathe. Your intuition will probably be pretty good. 🙂
This has a lovely ethereal sound. Try listening to some choral works to get ideas about how to use text and build sound. Here's one I like a lot that has a similar slow cathedral sound, but with funkier harmonies and more parts. The text translates to " O Master of all living, bestowing priceless gifts upon us."