I remember very well my frustration when I first started to learn to play guitar. You have an advantage, since I was also learning to read music in addition to where that note was on the fretboard.
From your description, there are two things that seem to be the problem; where is the note on the fretboard , and how do you place your finger accurately when you are not looking.
I had exactly the same problems and as others have said, this is perfectly normal in the beginning. Putting your finger on the wrong string for the note you want to play can be caused by not knowing the proper fret and string for the note, and also (if you are not looking) a change in the position of the guitar. I remember every time I first sat down for a practice session or changed to a different chair, the angle I held the guitar changed slightly and that caused me to miss the string I wanted to fret. The advice that Stephen gave, to memorize the scale and for a while look at where you are placing your fingers, worked for me. Also, to help cement in my mind where the note is on the fretboard, say the note name out loud as I played it. By looking at my fingers, I developed a clear mental picture of what pitch was associated with that position, as well as accurate placement .
I was still occasionally flummoxed by a really different chair height when I made a large shift up the fretboard, and missed my target strings. Until I get "indexed" into guitar in that situation, I still have to look briefly when making a large shift.
Time and practice will get you there!
When the sun shines, bask.
Classical Guitar forever!