I gave my DD meats and vegetables at around 5 months and she started with fruits (just tiny nibbles) at 4 1/2. But, she was totally ready - sitting unassisted and really, really wanting it! NT or no NT, I would definitely wait until the baby wants the food and isn't doing that tongue-thrust thing anymore. But once you get to that point, egg yolks are just fine as a first food.
I started my little one, who just turned 8 months, on bananas at 6 months. He REALLY wanted them beforehand, but I made him wait. If I do it again, I would have let him have then when he was ready, instead of making him wait. He ate a whole banana his first time!
When we started, we mashed them up really well with a fork, and started out with tiny amounts, so he could get used to swallowing something new. Now he just eats small chunks, he doesn't want it mashed anymore. At 8 months, he is eating all kinds of vegetables, cooked and raw. The raw ones he still gets really small amounts of so there is no choking hazard, I usually just bite off a little for him and give it to him that way. He also eats cantalope, watermelon, mango, peaches, and plums.
We tried giving him egg yolks for a long time, but he never really took to them. He would make awful faces and spit them out. I tried them the way the Weston A. Price website says to cook them, and added butter, but he just wouldln't eat them. I finally gave up and gave him scrambled eggs. He LOVES them, and since that's what I fed my 13 and 11-year olds when they were babies, I decided it was ok for us to try. I have also given him meat a couple of times, but he isn't too impressed with it yet.
Oh, and raw goats milk! He is still nursing but he loves it when his daddy gives him goats milk from his glass. He looks at him like "how come you didn't give me milk before!"
I agree with the above poster, definitely wait til your babe is showing all the signs for solid food, and WANTS it! I have friends with little ones who really didn't eat solids til 1, and now eat everything they can get their hands on, mine was just ready earlier.