adorable
You can never go back to that innocence level that you had during H.S./Sem; but you can be on a higher level in a different way. Just cause you have seen things you wish you hadn’t (and once images are there, they are there), doesn’t mean you will stay on that level forever. This is what life’s about: struggling, and fighting your way through so that you come out on top. As an innocent child/teenager, you haven’t experienced life & its’ difficulties & temptations, so your spiritual level is not based on personal struggles. Once you have made mistakes & force yourself to rise above them & focus on what positive things you can do, you become a much stronger person, because you have actually struggled through it. Don’t get caught in the yetzer harah’s web of look-what-i’ve-done-i’ll-never-be-good-again etc, because it’s just a trap to make you feel bad about yourself. Focus on the good parts of yourself & the good things you’ve done & can do, and iyH you will succeed.