I’m not sure you do understand. Lehigh, for example, has a 30% admission rate and academic rigor of high school courses is “very important.” You will not pass that threshold, even if you do take those classes spring and summer.
I don’t want to discourage you, but you do need to be realistic. Rigor means AP or equivalent in math, science, and probably at least 1 other area. Kids taking AP cal BC are completing the equivalent of cal 1 and 2. Some of kids reach that threshold in their jr yr and take linear alg, multivariable cal, etc. Some even get their younger.
Even if you complete pre-cal and physics, your high school courses are avg and do not pass the most rigorous threshold for schools with such a low acceptance rate. Look for schools with over 60% like @sbjdorlo suggested.
You can still become a civil engineer. You may just have to take the detour route. Starting off at a CC and transferring is a viable option.