Today I was asked if I would be a friend’s “surrogate daughter” for an upcoming triathlon at the end of July. I accepted. I haven’t seen the exact stats for the triathlon yet, but I’ve been told it’s about a 5k run – 2 mile swim – 10 mile bike.
Let me give you some background info. I’m a teenager, more on the academic side than the athletic side. I’ve played basketball since kindergarten, but was never super serious about it (especially in the later years). I dabbled in a few other ball sports (softball, volleyball, etc.) but didn’t stick with them for more than a season or two. In middle school I was on a swim team, but ended up dropping out because I had one too many experiences with nearly drowning during swim meets (due to exercise-induced asthma, presumably exacerbated by the cold water – not my swimming capabilities.) I’ve always enjoyed biking during the summer, but much to my chagrin, the past year I haven’t had a working bicycle (planning on buying one in the next few weeks).
Most importantly, for some time now I’ve suffered from a mysterious medical issue that has caused me to spend the remainder of the day curled up in the fetal position with a severe migraine every time I run or get my heart rate up really high, even for a fairly short time (seriously, I’m not making this up. It’s HORRIBLE.) Sadly, this has caused me to avoid vigorous exercise in recent years. Thankfully, the condition has been improving greatly with some dietary changes, and in the past month I’ve been gradually building my [formerly pitiful] running endurance.
With aforementioned dietary changes, I’ve also been dropping weight quite quickly, and I’m nearly at a normal BMI (29.0 on March 15, currently at 25.4 and going down.)
So, here’s my question: how should I train for this in less than 3 months, starting at a fitness level of nearly zero? I’m willing to do it, and I believe I’m able. I haven’t had time to figure out a complete plan yet, but right now I’m planning on doing C25K for the running portion. Haven’t figured out the swimming portion yet.
Running is the biggest priority for me, followed by swimming, and biking last (I’m fairly certain I could bike 10 miles even at my current fitness level.) My main concern is overdoing it and being set back by migraines or a minor but painful injury. Tips and encouragement would be appreciated!

First of all I would see a doctor about your exercise induced asthma and other medical concerns. My daughter is a runner and she has that--and they corrected the problem with an inhaler. If the doctor gives you the go ahead for the event--then start out slow--in your training and work up to the 5 k the 2 miles of swimming and bike riding. I think you could do it in 3 months. There's lots of training ideas on the internet from others who have done triathlons that would be very beneficial to you. I don't look at these type of events as you need to win or place--just finishing deserves a metal--and I am certain you're capable of doing that.

Talk to you Doctor before you commit to this.

I'm a triathlete and currently in training. 3 months is plenty of time for the distance you're looking at. I don't think the swim will be 2 miles. A half Ironman isn't even a two mile swim and a full Ironman is a 2.4 mile swim. I'd imagine your swim to be more like 300-400 yards.

A Super Sprint triathlon is typically a 300y swim, 8 mile bike, 2 mile run.
A Sprint triathlon is 300-600 yards, 12-24 mile bike and a 3.1 run.
An Olympic distance triathlon is .93 mile swim, 25 mile bike and a 6.2 run.
A Half IronMan is a 1.2 mile swim, 56 mile bike and a 13.1 mile run.
A Full IronMan is a 2.4 mile swim, 112 mile bike and a 26.2 mile run.

Your biggest priority needs to be your weakest area. I would imagine that to be swimming. (It's most people's weakest area) My advice is to spend as much time in the open water practicing as you can.

Agree--I thought 2 miles was a little too much for a triathlon. My husband did one and he only swam around 200 maybe less yards--(across the lake anyway.)

Thanks guys! As it turns out, the person who told me those lengths was way off (I did think that a 2 mi swim sounded crazy!). It's actually a 10 lengths swim, 2 mile run, 7 mile bike. Far more manageable!
Plus, I will probably be joining a beginner group that's training for it under a certified instructor. I'm sure that will help a lot.

That's a Super Sprint triathlon. The shortest one available! If you're talking about a "10 lengths" swim it may even be inside of a gym, which would eliminate the dreaded open water swim.

Good luck and have fun!