Consumers are ready to spend this holiday season _ right?

Americans, by most measures, appear ready to shop this holiday season.

Consumer confidence is at a 17-year high, while unemployment is at a 17-year low. The economy appears to be humming, with growth of 3 percent at last measure. And initial numbers show millions more Americans shopped over the long holiday weekend than last year, spending an estimated $335 on average on gifts and other items, according to National Retail Federation.

But other indicators suggest there may be less merry times ahead.

"I am generally positive for this holiday shopping season that consumer spending will be robust, (but) the economic growth we are seeing may take a downturn next year," said Robert Murphy, an economics professor at Boston College.

Initial numbers for the holiday shopping season are just that, initial. The full scope of the holiday shopping season won't really be known until January when the Commerce Department reports its retail sales numbers for December. Plus, there are signs that consumers may be under a bit of a squeeze.

Consumer borrowing is up as Americans take on more debt for auto and student loans, according to Federal Reserve data. Borrowing for revolving credit, such as credit cards, is up too. At last measure, Americans' total borrowing is at $3.79 trillion. That does not cover home mortgages or other loans such as home equity loans that are secured by real estate.

Americans seem to be tapping into their savings for this increase in spending too, as the savings rate has fallen since the middle of 2016, said Lara Rhame, senior economist at FS Investments. That happened during the last economic expansion and it proved to be an unhealthy move.

Also, unemployment is so low in part because many people stopped looking for work and are no longer counted as unemployed. Income, the biggest indicator of a consumer's ability to shop, is a muddy area too. Pay gains are sluggish as companies struggle to increase prices and wages in a low-inflation and weak-productivity environment.

Why does it all matter anyhow? It's important because any pressure on the consumer could hinder spending — and consumer spending is the biggest driver of the U.S. economy, accounting for about 70 percent of economic growth. And a good chunk of consumers' discretionary spending occurs in November and December. For some retailers, the holiday season can represent as much as 30 percent of its annual sales, according the NRF.

"Consumer spending is a big ship, so it tends not to move much up or down, but it just has to move a little bit and there are big consequences," Murphy, said.

At this point, it appears things are looking good for this holiday shopping season. Still, experts say the 3 percent economic growth in the U.S. may be a bit too high to sustain for much longer.

"If you look at where the upward momentum comes from, it's hard to see consumers accelerating from here," said Rhame. "Without wage growth, I don't find them able to accelerate."

Rhame also points out in her research that while consumer confidence has been soaring, that hasn't translated into actual spending at retailers.

The two typically move in lockstep, but retail sales growth has been decelerating for years. Since 2014, year-over-year sales growth has averaged about 3.4 percent — much lower than the 5.3 percent seen from 2010 to 2013. That has her concerned because a slowdown in consumer spending could pull U.S. growth lower.

"Cash dollars going in the register is what really matters in the end," she said.