From Mashable:

When I asked Resolve about the age groups of iPad users, I found out some other interesting information. The first owners of the iPad tended to be young professionals, 22-45, who were either early adopters in general or had a highly connected and mobile lifestyle.

However, the next group of adopters and those interested in buying an iPad are much older than the one might expect (45+). Anecdotally, I've seen this in my own travels and discussions with iPad or future iPad owners. The first wave of iPad owners were people like myself. The second wave of iPad owners, at least from what I'm seeing, have more in common with my parents.

Not surprised. I’ve been discussing this with a few friends. If the iPad had been around before, this would have been the device they bought before an iPod. Using it is so easy to use, I can’t imagine older users having issues, especially with a clearer, larger screen than an iPod.