Term for when someone gets overly pepped up and thinks he/she can do anything

Solution 1:

thinking that you can do more than you really can, can be called delusional, cocksure, overconfident...however none of these imply that the overconfidence was induced by other people.

Someone who allows other people to convince him that he can do much more than he really can could be called stupid, dense, simple-minded, foolish, daft and many more - unless he has some mental issues, in which case none of these apply: it would be someone being subjected to abuse.

To describe what you want you need to create a phrase, for instance "praise-induced delusion" or "pep-prompted cocksureness"

EDIT:

from comments to other answers it seems the OP wants the usage: "Don't get _, you can't drink all that in one go". Hence:

"Don't get cocky, you can't drink all that in one go"? - this can be taken as advice or as a challenge, depending on too many variables to list

"Don't be stupid(or alternatives), you can't drink all that in one go" - disclaimer: use at your own risk

Solution 2:

It's called a manic state (enthusiasm, often of an extreme and transient nature) in medicine. There is excessive energy, often accompanied by creativity, increased work output, sleeplessness, grandiosity, impulsiveness, even psychosis and thoughts and schemes that may lead to self-neglect. It is not induced by othe people, though, but lay people still refer to people with high energy levels (for whatever reason) as manic.

A more common and less specific term might be hyper (very excitable or nervous; overexcited; keyed up), or hyped, revved up, keyed up, or (one we use a lot in our household) rabid.

There's also psyched.

Hyper is defined in the UD as a short term feeling of having lots of energy; one who is hyper usually does crazy/stupid things and laughs a lot. Often called a "natural high" and is caused by mutliple things: friends, sugar, lack of sleep, night, etc

Solution 3:

Perhaps slightly obsolete slang: "jazzed." You could use "overconfident" for a less-than-manic description.

Solution 4:

The force exerted by those around the person is peer pressure, and is far more specific to that phenomenon than other suggestions here. Thus, you might consider rewording the sentence:

Don’t give in to peer pressure; you can’t drink all that in one go.

While this doesn’t quite fit the grammatical location you wanted to put this term, it will carry the more specific meaning you’re looking for better than more generic terms for being overconfident.