In the blink of an eye

Solution 1:

In the blink of an eye is a very short time in its literal sense. There is no need to use "like" here— it isn't like an instant, it is an instant.

Time flies is an idiom which evokes the general sense that it moves quickly, and more quickly than we perceive it, but not necessarily in an instant. The old saying is Time flies when you're having fun, meaning time seems to pass more quickly when having fun, but not that the fun is over with as soon as it started.

They are both clichés, and I would try to think of better expressions perhaps more directly related to the topic. If you do use one, remove the other, as they are redundant. You could say, for example,

My first year at university passed in the blink of an eye.

Time flew during my first year at university.

Solution 2:

Time flew during my first year at university.

My first year at university passed in the blink of an eye.

Grammatically, these are good examples, but I'd like to expound.

Time flew implies time went by quickly.

In the blink on an eye implies something happens in an instant, such as a sudden, unforeseen calamity.

Hence, I have no problem with "Time flew during my first year at university," but it's hard to resolve a one-year event happening in the blink of an eye.

So, I would suggest:

Time flew during my first year at the university.

Things were going well during my second year at the university, then, in the blink of an eye, my world was turned upside-down.

Solution 3:

Not quite. Something that happens very quickly can be said to happen in the blink of an eye, but not time itself.

Solution 4:

the wink of an eye, or the blink of an eye?

Here's an Ngram: