note: this may be just my personal take on it and others may completely disagree and thats totally ok. Also note ive gotten really similiar speeches directed AT me myself.
I don't think anyone is ever truly "ready" for their first AA. the experience as a whole can be fairly overwhelming when taking into all the planning and arrangements, producing artwork, pricing, getting equipment together, etc it just bowls you over, and even with all the great planning, you still can easily feel caught off guard.
Here's the thing, you should do the artist alley regardless, if only to chalk it up to a learning experience. Hearing what to expect and actually experiencing it are two totally different things. If you walk away with anything from it, walk away with an idea of what to expect next time, a list of what works and what doesn't, and try to make a few contacts with both artists and attendees.
draw or write, or produce whatever it is YOU want to produce, the enjoyment will show through. Dont go into it expecting to make some huge profit. Go into it to just have fun. Go into it to make some new friends, Go into it, expecting to know 100 % more about the artist alley experience than you did before. Note your mistakes, reevaluate, and learn from them.
In short, go ahead with your alley plans, because it'll be good for you.