be too

be too

To be able or permitted to do something. This construction is mainly used for emphasis in short sentences that typically end with "too" or follow "too" with a verb. A: "You aren't allowed to have sweets this early in the day." B: "I am too! Mom said I could, just this once." A: "You guys aren't allowed to be here this late!" B: "We are too allowed! Let us in!"
Farlex Dictionary of Idioms.

be too

 and be so
to be something (despite any information to the contrary). (An emphatic form of is, am, are, was, were.) Mother: Billy, you aren't old enough to be up this late. Billy: I am too! I was so! I was there exactly when I said I would be!
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • be so
  • have so
  • have too
  • do so
  • do too
  • emphasis
  • lay emphasis on
  • lay emphasis on (something)
  • How are you feeling?
  • How you feeling?
References in classic literature
"Nothing of the kind," answered the Duck, "every one must make a beginning, and parents cannot be too patient."
The Happy Prince and Other Tales
I may burn out more quickly than other temperaments by trying to be too helpful.
4 ways to become holy