What's the earliest age to get a stroke/ heart attack?

My friend who's 27-years-old had a stroke, the doctors say it was triggered by stress. I'm 23 years old and my heart beats extra fast from time to time, I find myself anxious a lot. I used to suffer from depression until I started meditating, but it's as if my body's chemical balance is so used to being depressed because I still get those rushes to the heart that beat too quickly, as if I were scared,..... Could I be prone to getting a heart attack??

I've also found that my toes get numb for no apparent reason.

Yes A child can have a stroke in the womb or any time there after Please do not let your friend's Dr. insist that he/she had a stroke because of stress. To have one at that age is most likely brought on by a clotting disorder. Strokes do not just happen. I am a young stroke survivor from a disease that I had no clue that I had until I had a stroke.
As for your rapid heartbeat, You should be examined, and mention the numbness as well. An anxiety attack can cause the racing heart and it can just last a few seconds. I would not panic, but be aware and document when it happens, symptoms and how long each episode lasts. Take this with you when you see your Dr.

its possible - I've heard cases in teenagers- its very rare but it happens.

A doctor is the only one that can definitively tell you if you are at risk or not.

In the womb.