Especially at your age, the real question is, "will i be an adult with a health-focused lifestyle, or not?" if your LDL
cholesterol is concerningly high, it'll take more than oatmeal
to fix it; it'll be lifestyle and maybe if that fails, medication, and oatmeal won't be the key.
If not, why not make your oatmeal decision based on whether you like it or not?