I presume you’ve checked with the specific colleges you’re applying to about this because as a general statement about all colleges it’s not true. There are a fair number that do not allow courses taken in high school to count. My three boys went to three different colleges. Two allowed their high school college courses to count. One did not (the highest level one). FWIW, their high school college courses weren’t on par with those their peers at the 4 year schools took (their opinions), so be wary if expecting to have as solid of a foundation as your peers in your college classes. That will depend upon the material in the courses and how they compare - not the syllabi, because those can be similar, but what was actually covered.
From what I’ve seen regarding high school students and whether they should expect credit is worthy or not, check with the professors in the dept at your destination school. They’ve often seen enough transferring of credits to have a good idea.