I want to say that at some point in my life, I had to choose between two majors for undergraduate studies. Is this sentence grammatically correct?
I was in the dilemma of choosing between y engineering and z engineering to study as an undergraduate student.
Or should I say
I was in the dilemma of choosing between y engineering and z engineering on which major to study as an undergraduate student.
The preposition in the first sentence is correct. Change the beginning to "I faced the dilemma of..."
Perhaps you should avoid using the word "dilemma"
A situation in which a difficult choice has to be made between two or more alternatives, especially ones that are equally undesirable: he wants to make money, but he also disapproves of it: Den’s dilemma in a nutshell (www.oxforddictionaries.)
That is what "being on the horns of a dilemma" or "facing a dilemma" implies, trying to make impossible choices.
Most people don't use dilemma in this strict sense, but if you are writing to academics they may understand it that way; or even worse as indecision.
Choose a simpler word, more direct, such as choice, or hard choice.
My partner, another good way of expressing that you are in a quandary, is by using the noun "toss-up". The way you construct the phrase is by saying:
"It is/it was a toss-up BETWEEN/WHETHER" (when you want to talk about a quandary)
or
"It is/was a toss-up WHETHER" (when you talk about the possibility of something to happen or not to happen)
For instance:
"It was a toss-up between y engineering and z engineering to study as an undergraduate student"* (people would understand that YOU are in that quandary if you previously mention yourself in the situation).
or
"It is a toss-up whether I go or stay"*
[TO TALK ABOUT A QUANDARY]
and
"It was a toss-up whether prices would go up or down" [POSSIBILITY, NOT a quandary].
Check it: http://idioms.thefreedictionary.com/a+toss-up
My regards!
Your whole sentence is a little bit awkward. Perhaps you could rephrase it to something like:
I was torn between studying Electrical Engineering and Computer Engineering as an undergraduate student. (but of course I came to my senses and chose CE)
