Ok, so the underlying crime you are charged with is apparently:
Florida Statutes > Title XLVI > Chapter 893 > § 893.13 - Prohibited acts; penalties.--
(1)(a) Except as authorized by this chapter and chapter 499, it is unlawful for any person to sell, manufacture, or deliver, or possess with intent to sell, manufacture, or deliver, a controlled substance.
Since you state that you are being charged as a 1st degree felony, then you must either be accused of trafficking in more than 10 gm or doing so in an enhancement area like around a school.
Now, since you were buying, rather than selling, how do you get charged with trafficking? Well, making a careful reading of the above statute, you will notice that it talks about possession "with the intent to sell, manufacture, or DELIVER, a controlled substance." Since you and your "friend" went in on this transaction together, you are considered to have "acted in concert" - meaning you both actively engaged in activity intended to facilitate the completion of the crime...the crime of possession. However, there is also a reasonable conclusion from your circumstances that you also intended to share the fruits of your illicit transaction - meaning once you got the drugs, you intended to share them with each other. Therefore, you are both equally guilty of possession and equally guilty of having the intent to DELIVER a part of the substance you illegally possessed with the other. So, you possessed with intent to deliver a controlled substance.
And, where does the conspiracy come in? For that, we need to look at:
Florida Statutes > Title XLVI > Chapter 777 > § 777.04 - Attempts, solicitation, and conspiracy
(3) A person who agrees, conspires, combines, or confederates with another person or persons to commit any offense commits the offense of criminal conspiracy, ranked for purposes of sentencing as provided in subsection (4).
Since both you and your "friend" willingly agreed to commit this crime together, you joined in a conspiracy.
As for advice for what you should do or say? The only competent answer to those questions are going to come from your public defender. 4 days prior to your prelim is plenty of time to strategize. Understand that these are serious charges and the legal process is likely to take months to shake out. Don't talk to anyone other than your attorney about anything having to do with your charges.