AT THE BEGINNING of this presidential election cycle, I planned on waiting until shortly before the New Hampshire primary to decide whom I would vote for to be the Democratic nominee for president. For the last 30 years, I’d chosen my candidate early and become active in their campaigns. This time I just wanted to observe the candidates from the sidelines.

A few weeks ago I changed my mind and decided to support Kirsten Gillibrand for President. Let me tell you why I think she’s the best Democrat to beat Donald Trump.

Elections are about contrasts and I believe Kirsten Gillibrand is the perfect contrast to Donald Trump in policies, but also in personal qualities.

Trump is a low-energy President. He doesn’t show up in the Oval Office until 11 a.m. most days, spending his mornings in his bedroom watching TV and tweeting. His public schedules are light. Almost every weekend he heads off to one of his resorts to golf and hang out with his rich donors who dictate his agenda.

Kirsten Gillibrand bursts with youthful energy. The first time I saw her at a New Hampshire Young Democrats event in February, I was struck by her exuberance. She was eager to answer questions and share her vision for the country. She showed a level of excitement and optimism for the future of our country I hadn’t seen in a while. It was contagious. It lifted my spirits.

I am tired of baby-boomer Presidents. We’ve had four in a row — Bill Clinton, George W. Bush, Barack Obama, and now Donald Trump. Twenty-eight years of baby-boomer Presidents is enough! Baby-boomers, and I am one, have had their chance. It’s time to turn the reins over to someone younger than I am.

We live in the greatest country in the history of the world, yet there is so much anger and unhappiness and division. Donald Trump is a sour and grouchy old man who tries every day to further divide us and stoke our anger.

Coming from a conservative district in upstate New York, Kirsten knows how to bring people together on both sides of the aisle. In her most recent re-election, she flipped back 18 Trump districts. That speaks to her ability to unite, something we desperately need.

Kirsten Gillibrand is also a happy warrior. We could use some joy in the White House after four years of Donald Trump, don’t you think? And as Kirsten herself has said, “Imagine what it would be like to have a working mom in the White House instead of a misogynist.”

I don’t agree with Gillibrand on every policy issue. But I know her positions are carefully reasoned. She is a policy wonk. Donald Trump? He doesn’t even read. If I hear him say one more time that China is paying for the tariffs on Chinese goods he’s imposed, my head is going to explode. Being smart isn’t everything, but I’d like the President of the United States to at least understand the issues the President is dealing with.

I also like Kirsten Gillibrand’s grit. She sticks with issues and doesn’t give up, like obtaining permanent benefits for the firefighters who responded at the World Trade Center after the Sept. 11 terrorist attacks. She’s relentless. She entered the presidential race as an underdog and she still is, but she doesn’t give up.

I’ve taken advantage of the opportunity we have in New Hampshire to see presidential candidates in person, and I’ve been impressed with the Democratic candidates for President I’ve been able to meet.

But I’m convinced that Kirsten Gillibrand is not only the best candidate to go up against Donald Trump, but the person with the right personal qualities to lead this country at this time in our history.

Judy Reardon is the former Legal Counsel to Sen. Jeanne Shaheen.