Helen,
Many TS give certain recommendations for choosing a name:
Try to feminize/masculinize your given name if possible.
Choose a name with the same initial as your given name.
Choose a name that was popular the year you were born.
Choose an ordinary, everyday name, not a unique or unusual one that will "stand out".
But that's all they are - recommendations. I wouldn't adhere to them too rigidly. Rules are meant to be broken!

Just as Melissa said. Choosing a name with the same initial as their given name makes the name easier to get used to for some, but more importantly,
it has to be a name that you like and can handle answering to for the rest of your days.Unless you really can't find a name that suits you, I don't feel you should stick with a name that you feel ambivalent about.
That being said, I really like the name Helen. It's feminine and elegant.
Some other
H names I like:
Harriet
Heidi
Hilda
Holly
Hope
or you could just add an "a" to Helen - Helena (beautiful, though it has a sad connotation for me)
Good luck.
Nero