First off, anytime you go to a new area the default speed might be set to 1. Might wanna check that to the bottom left.
Second, what's the harm in giving you access early exactly? It doesn't cost any resources other than DT Keys to do the battles and there's rewards for each stage that are more valuable the newer your account is.
Third, you might wanna screenshot your roster so folk can give you advice of a team to use for DT floors.
Lastly, the level is gonna be higher and you can see 200s as well. It's to balance out their power since they don't have gear vs. your champions that do. I still remember how tough DT Normal seemed the first time I got there. In fact everything has that feeling of difficulty. But once you get a good team going and decent gear, it's super easy and you wonder why/how you ever struggled.
On the note of gear, Dragon is 3x Speed drops right now and that's probably one of the BEST sets for you. I mean it's a great set period but especially for new accounts