What's the difference between swiss and baby swiss cheese?

Yes, the age (and thus the taste) of the cheese is "less."

Here's a site that had a summary of the issue: 

Let us start with Swiss cheese. Swiss cheese is, clearly, highly recognizable for its holes.

These holes are actually called “eyes” by cheese professionals, and, I would assume, cheese connoisseurs. The holes come about during the process by which the milk is transformed into cheese. A (good) bacteria forms, and creates pockets of carbon dioxide, which are the holes.

Basically, the longer cheese ages, the bigger the holes get. And, according to GotCheese.net, the longer the Swiss cheese ages, the better quality it becomes. Also, the more intense it becomes.

Which brings us to: Baby Swiss. Baby Swiss cheese is not aged for very long, and so it is milder, which some people prefer. It is similar to another type of Swiss cheese, Lacy Swiss, and the two are often mistaken for one another; I had never heard of Lacy Swiss cheese prior to today.

Baby Swiss was invented by Alfred Guggisberg in the mid 1960s, and it has a buttery, slightly nutty flavor to it. And again, it is less hole-y and milder than traditional Swiss cheese.

It also should go without saying at this point that cheese enthusiasts would probably agree that baby Swiss cheese is of a lesser quality than the longer aged, stronger flavored Swiss cheese. Perhaps that is where the term “baby” came from, as a comment on how much more hardcore real Swiss cheese is.

http://www.erinnudi.com/2013/06/26/difference-between-swiss-cheese-and-baby-swiss/

If you want more information, search "baby swiss vs swiss"