I dont know when to go to Solstheim, im level 15 at the moment and i went there once and got wrecked by Ash Spawns and the cultists that you have to kill to start the main quest killed me about a dozen times. I want to go to Solstheim when i can survive there but not be overpowered i want it to still oppose a challenge for me. Its my first time going to Solstheim and i just dont know when to go. Any help will be appreciated

Level 25 and up would be preferred. Always best to be fleshed out a bit.

Thanks