AITA for telling my stepmom she’s not a “real grandma” to my son after what she said at dinner?

I (31F) have a 5-year-old son named Caleb. He’s the sweetest kid ever — shy around strangers, obsessed with space, and the type of child who still runs to hug me every morning before school.

For context, my parents divorced when I was 12 because my dad cheated with the woman who eventually became my stepmom, “Janice.”

To say our relationship has always been strained would be an understatement.

Janice has this habit of acting overly sweet in public while making little cutting comments when nobody else notices. Growing up, she’d say things like:

“Oh honey, maybe don’t wear that outfit.”

“Are you sure you want seconds?”

“No wonder boys intimidate you.”

Tiny comments. Constantly.

And whenever I got upset, my dad would insist I was “too sensitive.”

Over time, I learned to tolerate her instead of fight her.

When I had Caleb, though, something shifted. Janice suddenly became obsessed with playing “perfect grandmother” online. She posts pictures of him constantly with captions like:

“My whole world ❤️”

“Grandma’s favorite boy.”

Meanwhile, in real life, she barely interacts with him unless there’s a camera around.

Caleb actually prefers my mother-in-law because she genuinely spends time with him. They bake cookies together, build Lego rockets, read bedtime stories — all the stuff grandparents are supposed to do.

Janice HATES this.

She constantly makes passive-aggressive comments about how Caleb is “closer to the other side of the family.”

Last weekend my dad hosted a family dinner for his birthday. Everything was going fine until Caleb accidentally spilled grape juice on the tablecloth.

He immediately looked terrified and started apologizing.

Before I could even react, Janice loudly sighed and said:

“Well… SOMEONE clearly doesn’t teach him manners.”

The entire table got quiet.

Caleb’s face dropped instantly.

I told her calmly that he’s five and accidents happen.

Then she laughed and said:

“Kids behave differently depending on how they’re raised.”

That comment hit me HARD because she’s always implied I’m somehow a bad mother.

I started cleaning up the juice while Caleb looked like he was about to cry.

Then Janice says — and I swear this is exactly what came out of her mouth:

“If he were my child, he’d never act like this in public.”

At that point I snapped.

I looked her dead in the face and said:

“Well, he’s not your child. And honestly, you’re not really his grandma either.”

You would’ve thought I slapped her.

She immediately started crying.

My dad stood up and yelled:

“How DARE you say that after everything Janice has done for you!”

I actually laughed because WHAT has she done for me besides criticize me for nearly twenty years?

Janice kept sobbing while saying she “loves Caleb like her own grandson.”

But here’s the thing:

Caleb was literally hiding behind my chair while she made him feel bad over spilled juice.

So I grabbed my son, grabbed my purse, and left.

Now my phone has been nonstop chaos for two days.

My dad says I humiliated Janice and “weaponized biology” against her.

My aunt told me that being a grandparent is “about love, not blood.”

Even my husband thinks I may have gone a little too far with the wording — although he agrees Janice was out of line first.

But honestly?

I think years of resentment finally exploded out of me.

And the more I replay the dinner in my head, the angrier I get — because Caleb kept asking afterward:

“Why doesn’t Grandma Janice like me?”

That absolutely broke my heart.

Now I’m considering limiting contact completely, but part of me wonders if I crossed a line I can’t uncross.

So… AITA?