The answer is you can do it, but the real question is should you do it? Shaking and nervousness come from a lack of connection with the audience. It is a reaction to the primal question of is this person going to like me or are they going to try to kill me?
The way to get around this is to structure your presentation so that you get a positive reaction with the audience as you begin your performance. This usually doesn't involve doing a quick trick, but rather engaging in a conversation (in close up) or a reactive monologue (stage and parlor). This gets positive feedback in answers to questions, laughs or, most importantly, interest in what you are doing. When the primitive recesses of your brain realize that the audience isn't going to kill you and they like you, you will find that the shaking and nervousness dissipate. As proof of this, most people who are nervous say that they get over it after the first effect is completed -- why? Because they have gotten positive feedback from the audience.
As for forgetting words, that is because you haven't scripted what you are going to say and you haven't rehearsed the script (i.e. saying it while you are doing the effect) sufficiently. If you get to the point where you have rehearsed the script so that it come out as being natural there is a secondary effect beyond knowing what to say... you become less nervous because the words you say [and the silent script you say to yourself) are anchored to the actions you are performing. As a result, your brain focuses on what you are saying and your actions become automatic. Once actions become automatic, there is no more shaking.
Example 1
Magi: Do you want to see a card trick?
Spect: No. Oh, well OK.
Magi: Pick a card.
Spect: OK.
Magi: Look at is, show a friend, memorize it, put it back in the deck.
Spect: OK
Magi: Would it be amazing if your card was reversed in the deck?
Spect: Not really, but sure.
Magi: Look.
Spect: Pretty cool.. Can I go now?
Example 2
Magi: Human brains only remember a fraction of what we actually see... the rest our brains fill in based on a combination of prior experience and imagination.
Spect: [they make eye contact and when you pause you can see they are thinking about what you said]
Magi:When you drove here tonight, do you specifically remember starting your car? Do you specifically remember locking the door when you left?
Spect: [one or two will smile or react in a way that says they really don't remember]
Magi: [Looking at one spectator that reacted]. Yeah, exactly. [Looking at everyone] When you drive to work, do you remember the details of everything you pass, or do you just notice things that are different than usual? If there was something different, something really out of the ordinary -- like a dozen cows on the interstate... you would remember that. But if it is a typical commute, you wouldn't be able to remember any of the mundane details.
Spect: [people will react by thinking and by internally saying, "yeah, I never really thought about that, but I do"]
Magi: I want you to do something mundane. I want you to pick a card... if you've ever seen a magician before, picking a card is so standard, it is almost cliche. [Spectator picks card]. What makes this different, is the card you picked. Because that is different, I want you to remember it and show it to your friends so that they remember it. Now stick it back in the deck. [Spectator sticks it back in the deck]. Typically, this is when the magic trick usually begins, where things get exciting [hands deck to another spectator]. Sometimes buried in the mundane, is the mysterious. In not paying attention to the ordinary, we miss the extraordinary. What card did you select?
Spect: The Eight of Diamonds.
Magi: Although you selected a face down card out of a face down deck and the replaced the same card face down into the same face down deck, I know that there is a single card in that deck that is face up. Wouldn't that be extra ordinary if that card was your Eight of Diamonds?
Spect: [looking at deck with other spectator and seeing their card reversed]. WTF? When did that happen?
Magi: When the ordinary becomes something extraordinary.