Don't worry! It is something you should get checked out, but its not an urgent/life threatening thing. Most likely your doctor/heart specialist will tell you that nothing needs to be done, as long as they don't annoy you too much.
Telling your parents is hard - I know what you mean. I was really nervous telling my mum that my doctor had decided to send me to a heart specialist. I thought she would probably freak out or think I was imagining my symptoms. She actually did a bit of both, but it was good to tell her. Later you could regret not telling your parents because they will find out eventually and wonder why you didn't tell them!
Whenever I need to tell my mama something that will freak her out, I try to do it calmly and stick to the simplest story. How about catching your parents when they aren't too stressed out, maybe cooking dinner, during an ad break on tv, walking the dog, or loading the dishwasher. Calmly say, "By the way, Mum, I've been feeling like my heart skips a beat every few months. I think I should go to the doctor about it."
Don't worry, your parents won't have a heart attack
when you tell them.