How can I make my dad realize I can't get into the colleges he is convinced I can get into..?

Of course, it depends on what you mean by “selective school”. For example, in California, it is much harder to get into UCB or UCLA or CPSLO than it used to be. But if “selective school” is defined as “any UC” or “any CSU”, then it is not harder to get in than it used to be.