Idiom for becoming disillusioned

What idioms can be used to mean "become disillusioned with myself."

my reading speed is 300 wpm and I have always considered myself a very fast reader, but today ________ when I discovered that there exist "speed readers" who achieve better comprehension at 1000+ wpm.

If one has pride in oneself, they can "get shown up" by observing someone being better than them at that thing.

What other idiom has a similar meaning? The difference being particularly, that there doesn't have to be one specific person "showing them up", but that the person being disillusioned has just been made aware of something that points out they're not so hot as they thought after all. "Rude awakening" vibes.

One English idiom that might be relevant is "put [someone] to shame." Here is the entry for that expression in E.M. Kirkpatrick & C.M. Schwarz, The Wordsworth Dictionary of Idioms (1982):

put (someone or something) to shame to make (a person) feel ashamed of his work or to make (the work) seem to be of poor quality by showing greater excellence: She works so hard that she puts me to shame.

Longman Dictionary of Idioms (1979) has a slightly longer entry for the phrase:

put [direct object] to shame to cause (someone or something) to be considered as being of very low ability, poor quality, etc.; esp. by being better: his knowledge of our town, and even the history of the houses we lived in, put us all to shame || ... the municipal lunatic asylum, whose cast-iron railings and noble gates put our rough wire to sahme. (Evelyn Waugh)

And Christine Ammer, The American Heritage Dictionary of Idioms, second edition (2013) has this:

put to shame Outdo, eclipse, as in Jane's immaculate kitchen puts mine to shame. This idiom modifies the literal sense of put to shame, that is, "disgrace someone," to the much milder "cause to feel inferior." {Mid-1800s}

In the question poster's example sentence, the wording of the idiom might be as follows:

... but today I was put to shame when I discovered ...

My reading speed is 300 wpm and I have always considered myself a very fast reader, but today I got schooled when I discovered that there exist "speed readers" who achieve better comprehension at 1000+ wpm.

school / get schooled / take to school

school (one) (in something)

slang To show complete dominance over one (in something); to best one thoroughly (in something).

We really schooled our cross-town rivals in the final football game of the season.
Wow, your brother is crazy good at video games. He just totally schooled me! Farlex

school (transitive) To defeat emphatically, to teach an opponent a harsh lesson.

A blind law graduate who put the National Conference of Bar Examiners to the test got schooled in federal court.

Two weeks later, the Cornhuskers put on their road whites again and promptly got schooled by miserable Iowa State in Ames. After the shocking loss... Wiktionary

take to school

Similar to "schooling" someone; beating someone in a competition badly and thereby teaching them how it's really done.

John challenged me to a game of one-on-one, but I took him to school. Urbandictionary

"Rodriguez was a veteran and slick as hell. Whenever I hurt him, he'd slide and make me miss. I had more firepower than he did, but he took me to school a few times; knocked me down in the ninth round." Thomas Hauser; Black Lights

To avoid back-to-school scams, Moody encourages students and parents to keep these tips in mind... Francine Frazier; "Don’t get schooled by scammers, Florida AG warns"

The OP edited the question to focus on the feeling one has in the situation described. I suggest:

...but today I became disheartened when I discovered...

disheartened (adj.)

If you are disheartened, you feel disappointed about something and have less confidence or less hope about it than you did before. Collins

dishearten (v.)

To cause to lose hope, enthusiasm, or courage : to cause to lose spirit or morale were disheartened by the news m-w