I'm trying to learn sight-singing sheet music. I understand the basics such as the length of a note, time signatures and so on. But the only insurmountable difficulty for me is that I don't remember the pitch of the notes on the staff. It takes me more than a few seconds after I see a note to figure out how high its pitch should be. I know that people who have learned a musical instrument such as the piano have instant reflexes when they see a note, because they have played those notes thousands of times. But I don't have this ability.
A lot of people claim it is possible to learn sight-singing sheet music without having learned an instrument, but I've grown ever suspicious, because I had once tried quite hard to remember the notes, with no success. I've learned where the notes are located on a keyboard, but again all I have done is learning theory, and I never managed to develop an ability to instantly recognize a note as shown on the staff.
So do you think it's a valid idea at all for me to try to learn sight-singing, before I have time to learn an instrument? I'm sorry this question is a little dumb for most people on this board.