as Lark said, the future is always changing. sometimes just having the reading can effect the future enough to change it. the spread i use gives 2 possible outcomes. once the reading is done, you should forget about what the cards said, unless you've be warned about something.
the readings on this site are randomized, it's more for fun. the best thing would probably be for you to get a deck and a book, and learn yourself. it might take some time to get good at it, but it's easier [and cheaper] than relying on others. keep in mind, not everyone can read tarot, some are better with oracle or runes. personally, i read both tarot and oracle cards, but and terrible with runes.