Stealth is different in ESO than it was in previous Elderscrolls games. In Morrowind, Oblivion and Skyrim you could sneak around folks, front, back and sideways and not be seen / detected if you had 100 sneak skill.
In ESO everyone can sneak and modifiers are based on armor, class and racial passives. I don't know that there are any modifiers for level. If you are sneaky stabby type you might like Nightblade class with Cloak skill to help you move around unseen by timing Dark Cloak casts while in stealth.