Is it a good idea to change a character archetype when you're already invested into another one?

I've always liked playing a sneaky thief/assasin/archer and my first profile is just that. I'm level 28 (I can 4 shot a giant with crits) and I'm already almost 100 sneaking, 72 archery and light armor. I chose wood elf and I've completed the thieves guild quest line, working on Assasins guild and joined the storm cloaks.

After seeing some funny YouTube videos utilizing frenzy and telekinesis I kinda want to try that play style. Is it too late to switch it up? Can I be a competent archer and warlock? Or should I just make a new profile? At what level are you considered committed to your archetype? Thanks!

At Level 28 it is possible, Illusion has a problem of requiring almost every Perk to be used effectively. Alteration can be levelled by using Flesh Spells. Illusion can be very easy to level quickly once a character gets the Muffle Spell.

A Bound Bow is a very effective Bound Weapon, but it requires a minimum of 150 Magicka to cast without Perking Conjuration three times (Novice, Apprentice, and Adept).

With the Perk Reset available in Dragonborn, and Legendarizing of Skills that reach 100 it can be done if You choose to use Ranged Attacks to free up a few Perks to be used in Illusion without weakening Your character too much.

I do not like changing a character after level 20 because of the way opponents in the Game level, but Illusion can be fun.

I just made a new character and I'm level 18. Being a caster is tough, I have a problem with more then 2 enemies, especially in dungons where they resist my illusion spells and don't fight each eachother. I find it increasingly difficult to sneak around foes, I need to divert some perk points to stealth

Sure you can change, you could become more of a night blade (that's the right class, right?) My assassin did this. Got crazy high sneak+archery, then began studying illusion.

I could try that I suppose. I like that Bathsheba made it so you need to plan your character build and only give you set amounts of perk points

Do it now, because if you try to switch later on, you won't get as many level ups and getting perks will be harder. Right now on my level 50 heavy armored warrior sneak assassin, I tried to go for destruction just for the hell of it. It's nearly impossible for me to earn enough perks to spend on destruction