“Some birthday.”

Former President Donald Trump “winced” at supporters singing “Happy Birthday” not just because of his historic legal woes — but because he’s embarrassed at turning 77 on Wednesday, a source told The Post.

The birthday boy grinned awkwardly while he was serenaded a day early at Miami’s iconic Versailles Restaurant in Little Havana, where he headed Tuesday after pleading not guilty to 37 counts in federal court.

“Some birthday. Some birthday,” said Trump, looking like he was eager for the serenading to stop.

While he blamed it on “a government that is out of control,” a source maintained that his sour mood was an age-old response to his big day.

“Trump is [known for] hating his birthday, and never celebrates it in a meaningful way,” the source said.

“Insiders say he feels even more so this year as he doesn’t want to call attention to the fact he’s turning 77,” said the source, noting how the aging presidential candidate “winced” at the tribute.

While Trump’s wife, Melania, and youngest child, 17-year-old Barron, are expected to stay with him at his Bedminster golf course in New Jersey, any celebrations will be low-key, according to the insider.

“No big party is planned,” the source said, suggesting that the Trumps are only expected to have a family dinner, as they did last year.

Still, Trump’s historic legal woes allowed him to start his birthday in his age-old style — raging on Truth Social.

After an angry address from Bedminster, Trump continued posting angry messages until after midnight, attacking President Biden and pushing conspiracies that his legal woes were really an attack on his supporters.

“Joe Biden will forever be remembered as not only the most corrupt president in the history of our Country, but perhaps, even more importantly, the president who, together with a band of his closest thugs, misfits, and Marxists, tried to destroy American Democracy!” Trump wrote minutes after midnight.

Minutes later, he added: “They want to take away my FREEDOM because I will never let them take away your FREEDOM.

“They are not coming after me. They are coming after you. I just happen to be standing in their way, and I will NEVER be moving.”

Trump already became the first-ever president to face criminal charges when he was charged in New York over alleged hush-money payments to hide porn star Stormy Daniels’ claim of a quickie while he was already married.

On Tuesday, he faced a 37-count federal indictment over his alleged unlawful storing of national security information at his Mar-A-Largo estate in Florida.

Trump has pleaded not guilty in both cases.

Trump’s latest spokesperson, lawyer Alina Habba, did not immediately respond to messages seeking comment Wednesday.