New here, considering a triathlon

Hi all,

I am 43 and overweight (working on it!), but I've always been very active in various ways. I did the California International Marathon in 2014 and had my sights set on a triathlon as my next goal, but a breast cancer diagnosis set me back for another year. So now I'm starting from less than zero, trying to get back to my former level of fitness and I have a long way to go. I also gained a LOT of weight during my illness, so I'm watching what I eat and have lost a few pounds so far. Sadly, it's a slow process.

I'm signed up for CIM for this year because I had signed up for 2015 and deferred it when I got sick. Whether I'm up for the task remains to be seen, but I've been working out 6 days/week and improving with each one so I'm optimistic. I just have to listen to my body and do what I can. Sometimes I think I'm going to go for a run and it tells me no.

Meanwhile, I still really want to do a tri. I have not been much of a bicyclist since I've been an adult, but I got a Novara Jaunt for Christmas and have been riding a couple of miles here and there when I can. I think that will be the hardest part. I've been a swimmer all my life, although I struggle with breathing in freestyle and generally just do breast stroke. I guess I have to get that worked out! Right now, the furthest I've swam is 550 yards, although I was doing double that with ease before cancer. And of course running is ok, although I'm slow. My longest run since I've been back was 3 miles, and I felt great, but right now I'm only doing 1:00 run/4:00 walk intervals.

So the question is...is it realistic to do a tri this year while I'm still recovering from chemo, a unilateral mastectomy, and 6 weeks of radiation? When I'm extremely overweight and lost all fitness? When I'm also training for a marathon?