Welcome aboard!

If you are able to run a 10 mile run -- while being true to the training plan --- you shall be able to carry through to the end of 13.1

Since this is your first HM I suggest a conservative approach to the training. Do what the plan says, and you will finish -- of course, barring injuries, etc.

Although you have run in the past it does not sound as though you have a great base of running laid down. That is fine. But this is why I suggest the conservative approach.

I normally find one that I am comfortable with the schedule and go from there.  As you progress, constantly do body checks and make sure you are feeling ok (no odd pains, etc).  If that is the case, keep it up.  If not, pull back some and slow it down.

Right now, I am in week 4 of 12 for a 1/2 on May 6th.  I have used Hal Higdon's marathon training before, but decided to stay with the Active training program this time around.  Neither one is better than the other - just that it approaches the problem from different angles and gives you something to work towards until you reach the goal.  Without any training program lined up, I am not very productive.

I'm not an expert, but I've been training for a HM that takes place in 10 days.  My plan goes up to 13 miles, with a maximum of 30 mpw.  At this point, I wish I had done more.  I know I can finish, and probably could have finished a Half several weeks ago, but I found that I was fine adding miles up to about 11, then it seemed to get much harder adding distance.  Maybe it was psychological, maybe insufficient nutrition or hydration, but 12 and 13 miles were definitely more effort than 10.  If your body will allow, and you are doing sufficient miles on the other days (i.e. so your long run isn't 50% or more of your total), I'd go for a plan that gives you a bigger base before the race.

Although almost all my race experience is at shorter distances, I've done 2 half marathons, in 2008 and 2009. I used Hal Higdon's intermediate training programs because I wanted to race the halves for time, not just to finish. The longest runs I did in the half training were approx. 13 mi in 2008 and approx. 14 mi in 2009. I found that it was extremely helpful, mentally, to have done the full distance in training - there would be no doubt at the race that I would be able to finish, and I would know just how the last miles would feel. I would definitely recommend doing the longer runs if you can fit them into your training schedule.

I did notice, both in training and at the races, that despite my best efforts, I was consistently about 15 sec/mi slower after about mile 10. In 2009 it was particularly noticeable because I finished in 2:00:50, so that slowdown cost me the chance to break 2 hours. I chalked it up to a combination of relative inexperience (I'd simply done a lot more runs under 10 mi than over 10 mi) and subconsciously tensing up my legs after about 10 mi, draining strength from them.