Do Clyd/Athena's always go last?

Depends on the race.  NONE of my races had clydesdales going last.  It was a mass start for men, then women.  Also different starts for the different lenghts.

It doesn't matter when you start for your overall time.  The timing takes that into account.  But if you are worried about being the last one out there, probably doesn't matter too much when you start either.  They send the waves about only a couple minutes apart, so you will still be out there about the same time with everyone else.

BTW - Lady Clyds are "Athenas" in most cases!

As a fellow big person trying to do this sport - I would just stick to the Athena category.  You will be just fine!  If you are the last one, you just get to enjoy the course longer than anyone else!  It's just fine.....

I've done some races where the Clydes go off first.

Just think, if you come out of the water last, how many people you can pass on the bike.  

Race well and have fun! 

Most RDs put the Clydes last so there will be enough post-race food to go around.

  It seems like the bigger races have the older AGs go first (being in the 45-49 group this is my prefered set up) and the clydes/athenas go off closer to the end.  In the smaller, local fund raising tris it seems the younger/faster AGs go first. Usually in those races, there isn't an athena option.  I have never raced as an athena b/c of the late start.  In one race I did last summer there were still
waves starting 30 mins after my start. 
  I tend to be a mid to back of the pack swimmer, and yes, I love having lots of people to pass on the bike.  Of course, they all end up passing me on the run!!! 

It depends on the race like everyone else said.  You have until August to prep.  That is a huge amount of time.  Getting off the couch now puts you in front of everyone that hasn't yet.  Somewhere in the world some woman isn't training when you are and when you race you will beat her.  You should consider the BT 20 week to OLY training plan to help you out.

I recommend planning on getting to MOP swim so you never have to sweat it

I think the idea of putting the faster people up front and slower people in the back is safty  - less passing and "breaking though" mobs on the swim, and less passing on the bike. 

But O is right - there is not "always" in Tri....

If you are the last out there so WHAT?  Who is going to care?  Run your own race, register where you want - let other people worry about themselves.

I've been last in more than one race, and honestly, it's not that big of a deal - except that people cheer you a lot cause you're the slowest -  I'm not kidding.

I've even been last, and then got 1st place Athena.  I display that plaque with PRIDE, just so stoked that I got a medal... 

I hear you on the comfort level thing.  Oly is a big step.  But there will be a range of all abilities out on the course.

And... well, you mostly won't be alone (even if you are last) except towards the end of the run.  Check the course.  If it's out and back, you'll still see everybody coming and going.

If you can hold a bike pace of about 14+ and a run pace of 12 min, you'll be pretty close to the group.  I've always been ok on the bike mostly (although coming in towards the end) it's the run where I end up alone, as my running really sucks.  I think about a 14-15 min mile for my last Oly.   

You know you could always check the results from last year to see how long it took the last place people.  Then you should have a better idea of where you'd really be at in the race. 

My fastest Oly ever was 3:56.  Extremely proud of that, as I trained a LOT.  The run was what killed me, I am a slow, slow runner.

Get your bike ASAP and get outside, riding on the road is a lot different than on a stationary bike.  Of course, it's better than nothing, but not the same.

As far as swimming, have you looked at any of the stuff online for TI or drills?  I'd suggest not just pounding out laps in the pool but like doing say a 100 warmup then 100 of a drill, then 100 swim, focusing on what you just drilled on, and repeat.  Swimming is so much about technique and good form that it's worthwhile to put some serious time into the drill/swim routine. 

In the races I usually do, whether I go Athena or race Age Group, we still go last.  The RD groups Athena and 35+ women in the same wave.

I'm doomed to be last.  I've gotten used to it.