Questions and More Questions

Yesterday was day one of my 3 month 1/2 marathon training program. As I embark I have more questions than answers. Do I incorporate speedwork into the program or not? I want to get faster but I do NOT want to get injured. After Sunday's 4 miler (an all out effort) my legs ache in places I didn't know existed. I've read as much as I could on speed work and there are basically two camps. Camp A says speed work is not for novices and the chance of injury is high. Camp B says you can do beginner speed work to get faster. I can say that at almost 20 lbs lighter my performance has improved dramatically. However, at 170lbs I'm going to guess that my weight will continue to drop to about 155lbs in six months. I don't know how much faster that will make me or how much more I can lose beyond that based upon my genetic disposition. But, I digress. My thinking is that doing speed work at my current weight will only put extra strain on my ligaments. The 3 or 4 prep races I will have completed (fingers crossed) by the time the 1/2 rolls around will have been enough speed work. Plus Amy says don't do speed work in the winter. I'll defer to her. So its 5 days a week of increased mileage peaking around 29 miles prior to taper for the 1/2. I will throw in a tempo run or two just because. No intervals not yet.