So I think you are trying to ask whether to use "I've" or "I have" twice. The problem is that your sentence isn't a true present perfect situation. We sometimes use "I have" in place of the simple past tense, which is how you used it. Your sentence literally means "I went recently", and using "I have been" instead doesn't make it true present perfect. So your sentence is really just saying: "I went to the Education Fair recently, and while I was there I learned something-something."
A better example of true present perfect would be to remove the word "recently". Present perfect represents a space of time in the past that is unknown, so saying "recently" makes that space of time known. If we say, "I have been to the Education Fair," then there is a mystery about when you went, how long you stayed, how many times you have been there, etc. If we add words that clarify these mysteries, then present perfect starts to get complicated.
If we remove "recently", we would have these options:
(1) "I have been to the Education Fair, and I discovered a great deal of information there."
(2) "I have been to the Education Fair, and I have learned a great deal there."
Sentence #1 starts out sounding like present perfect, but the rest of the sentence makes it clear that you only went one time and you're describing your experience. This has the same effect as leaving the word "recently" in there. That changes the whole sentence to simple past tense.
Sentence #2 stays in present perfect because the mysteries remain. The explanation about your experience is also mysterious and doesn't provide any details about when it happened or how often it happened, so the whole sentence remains in present perfect tense.