Take up drums at age 56?

You should absolutely do it!! Age should have no impact on your decision at all.
I play the drums, and I'm 65. I do it almost everyday, and it always gives me great joy, though there are indeed times of frustration when I'm trying to play something and can't quite get it. 

As for the question about skip the practice pad, go straight to the kit, why does it have to be either/or? My opinion is using both would help you get better sooner, and by getting better I mean enable you to play things you hear and function around the drum kit, and that would lead to more pleasure for you.

Playing along with records, cd's whatever is a good way to grow your playing, (and a lot of fun) but you do need to realize that you're not gonna just sit down at the kit and magically play anything you hear. You're gonna have to put in some time on developing your ability (building your "chops") so you are physically able to play the things you want. Doesn't mean you can't also slam away, it does feel awfully good. 

Go for it, there's a very good chance you'll see the opportunity to fall in love with drums, (as I did) and if you get that feeling, finding a teacher and taking lessons would be something you might want to do. It wouldn't be an onerous task, it would be a joyous pursuit.

Btw, you can teach yourself, and these days there are lots of ways to get the info you need online. I was self-taught before the computer age. I spent 5 or 6 years working at it and actually ended up playing in bands that were fairly successful, and had a great time doing it. I got to the point where I couldn't grow enough on my own, so then I found a teacher (several actually) and got very serious about it. I'm not trying to make this about me, just trying to show you there are a number of ways to do it. 

Good luck, I hope you take the plunge

I say go for it. I did a similar thing . . . took up guitar in my 50's. I started teaching myself with books, online lessons, etc. In my case focusing on playing songs was key to keeping me going. After a couple of years of this I found a kid fresh out of college to come to my house a couple of nights a week . . . this was a big, big help in getting me to the next level (especially music theory). 

After that, I began jamming with friends. There is nothing more fun, and more important to your continued development than actually playing songs with people.  Second in line is playing with backing tracks . . . there are many many options for backing tracks to play with.  I now have a Jam studio in my house and 5-8 guys come over once a week for a Jam. I have a keyboard and an Alesis electronic drum kit set up there because these are tough instruments to schlep over. The other instruments (guitars/horns) are easy to cary over (though I have bunches of extra guitars and amplifiers. I also want to learn to play them. None of us really aspire to play in public (though we have) . . . too much work. We just want to play for ourselves for the fun, and to improve.

The Alesis electronic kit sounds great . . . our drummer is an experienced drummer and very good.  That said, I would be inclined to learn on an acoustic kit if I had a choice. 

Why not, if that is something that you are interested in?  Grandma Moses took up painting at 78, so you have a 22 year head start on becoming a well recognized practitioner of your chosen field.  

I would guess that it is easier these days to be self taught, given the amount of stuff that can be found on the web.  But, if you try it out and become serious, I bet live lessons would be a great source of fun and inspiration.

Thanks for the encouragement guys. Will have to see if that used electric kit hangs around the music store a little longer. I've pretty much concluded that an acoustic set would be my preference and also the best bang for the buck but would also get used way less due to sound levels. So if that used electric kit is around in a few weeks I might get the nerve to go get it.

I've been practicing on the new harmonica and have found that it is something I can do. In other words, I'm not even playing my way through a song but I can do all the things required to. I can hit all the single notes. I can bend notes. I can string the notes together with decent timing. What this tells me is that with practice I should be able to play this thing. Can already do most of the opening section of Love Me Do.