Angela Cartwright was born Sept. 9, 1952, so she was 13 on Sept. 15, 1965, when the series premiered.
Penny is 11 years old, has an IQ of 147 and is interested in zoology (No Place to Hide). That interest may be why she adopted the Bloop.
Her given name is Penelope (The Magic Mirror).
She once had a cat named Princess (The Lost Civilization).