JOEL - Your friend's answer to your question was basically correct. A young child and/or non-member would not be able to understand or appreciate the importance of temple worship and the symbolic meanings behind the things that are said and done there. And because of their sacred nature, we don't talk about them outside the walls of the temple.
The only thing that you need to really understand is the fact that your best friend has gotten married in a way that will keep her together with her husband forever, rather than just "until death do us part". Also, their marriage is not just a two partner deal, but includes Christ as well, devoting themselves to each other as well as to God.
The actual wedding ceremony is very simple. The bride and the groom meet with family and friends in a designated sealing room of the temple. The officiator typically greets the couple with a few words of welcome, counsel, and fatherly commendations. He may add other words of encouragement, with his blessing upon their righteous undertaking. The couple is invited to come forward and kneel facing each other across an altar in the middle of the room. As they hold hands across the altar, the sealer pronounces the simple words of the ceremony, which promise, on condition of obedience, lasting bonds with the potential for eternal joy between these two sealed for eternity. At the conclusion of the ceremony, the couple kiss over the altar and may then arise and leave the altar to exchange rings. That's it! A simple, short, but extremely spiritual experience that one never forgets.
The more ritualistic parts you are refering to actually occur during another ordinance called the Endowment, which is an important experience for the individual. This usually happens some other day before a person gets married, but some women do it on the same day as well. In the Endowment ordinance your friend has taken on sacred vows where she has promised God to obey all His commandments, keep herself morally clean and pure, and dedicate her time and talents to the building up of the kingdom of God(His church) while here on earth. The ritualistic parts of the ceremony are only tools that are used to instruct and help the person make these promises in the same way a person does when they are baptized with water.
Admittance into the temple is restricted to adult Church members who strive to live all the principles and doctrines of the Church. This includes being honest, keeping the commandments, such as chastity, sexual continence before marriage and fidelity within marriage, obeying the laws of tithing and the Word of Wisdom(no alcohol, tobacco, drugs, etc.), and fulfilling family responsibilities. Not all members do these things, which is why not everyone is allowed in the temple. This does cause some degree of disapointment and frustration when best friends or even relatives who are members are not allowed to attend the wedding of a loved one. My wife's non-member parents were a little upset because they could not attend their own daughter's wedding. However, they soon got over it and grew to accept it as a good thing after watching the rest of their children(not LDS) get married and then divorced soon after. My wife and I have been going strong and happy for 25 years now.
Don't concern yourself with the details of what is done in the temple; just be assured that it is the best thing that could happen to your best friend.