What is the complicated part? Is there a lot of math? Is it slow? A lot to keep track of?
Mostly the last one. There's math, but it's not complicated at all. A character sheet is littered with data of various kinds, all with impacts on game mechanics, so understanding all those bits and figuring out how to make them better is a major part of the game. Abilities, saving throws, equipment, armor, spell inventories, spell effects, spell ingredients, etc.* This is all stuff that was carried over from the olden days. They've added some new stuff, and added extra layers to some of the old stuff. For example, I noticed that there are more modifiers to armor and attack rolls depending on whether the weapon used is a pierce/slash/bludgeon weapon in the latest edition. It's just simple adding and subtracting of integers and rolling the dice, but it's more data to track and consider.
Even back in the olden days, the groups I played with streamlined the games. For instance, encumbrance. The rules say you're supposed to calculate the weight of all carried equipment, and compare that to a table for each player's strength, to figure out if they're overloaded. It also affects movement speeds. We just issued everyone a magic bag that had no limits and weighed nothing (think of Hermione's bag in
Deathly Hallows), and told people not to try wearing 200 pounds of armor for their 130-pound elf characters. Done.
We threw out spell ingredients, too. Nobody saw the fun in RPing frequent shopping excursions, nor in watching the party die because someone was short on ghoul blood or phoenix tears.
Basically, all the rules are suggestions, and the players and DM are free to modify as they like.
*Notice how the game gets a lot more complicated for players using magic. I recommend newcomers focus on characters who hit things, and expand from there. Hitting things is easier.
(She has one called a "sklate"--looks like a human, but its pupils are slits and it has no lips. It's telepathic, and if you get too close to one when you are under 10 years old, you will automatically kill someone you love the day you turn 11. The worst part is that you then regain your senses and realize what you've done, just before you die. Yeah, DD has quite the imagination!)
Holy crap, that is awesome, and yet frightening. Your DD isn't going to be 11 soon, is she?