To access Shadow of the Erdtree's new region, you will need access to Mohgwyn Dynasty Mausoleum in Mohgwyn Palace. Level 100 - 150 is recommended. 

That means defeating a hard as nails bosse, folks and many hours of gaming from the start of NG+. I never beat the final boss cause I couldn't beat Melenia so I'm good but still going to run through the later game areas again to reacquaint myself.

Reviews are in and the consensus is that it's a large DLC, well done but much more difficult over the base game. People are praising it and at the same time slighting the DLC on it's difficulty spike. 

Are you prepared?

Currently about 50-60% through a new appreciation playthrough and I estimate I'll have completed it just in time.

I have a character ready. I beat every main boss in the game including Malenia, I solo'd her on my 5th try.

Are you concerned about being over leveled. I'm in the same boat as you at like level 170, trying Melenia and two or three of the last bosses. Got the Elden beast ready to go and unsure if I should go NG+ right up to Mohgwyn or restart and do just that or stay where I'm at. 

My character is level 172, reinstalled the game yesterday but I won't do a NG+ playthrough.

I might make a new character and play with friends from the beginning to the DLC

I'm not too worried.  Based on the DLC of souls 2, 3 and blood...  not sure being over leveled is a thing with From.  

Supposedly there's a Sekiro-like attack powerup mechanic for attack in the Land of Shadows so no one isn't going to be too overleveled.

Whata ya mean? They're hard capping leveling?

No, there's a new attack mechanic in the Lands of Shadow. You won't deal much damage anyway unless you level that up, so (supposedly) your starting level doesn't make that much of a difference in your damage output.

Of course, you'll still want to have vigor or other stats relatively high beforehand, I suppose, hence why Mohg is the beef gate of the DLC.

Can you access the DLC from NG+?