I'm going to make a suggestion that is revolutionary. I doubt very seriously that your Mom expects that you will go throughout life never kissing someone you are interested in romantically.
Tell her you'd like to kiss this girl, and ask her advice on how you should do it.
You may be surprised at the support you get, and if you ask her privately, nobody else need know that you asked.
And I can guarantee you that it will make your Mom's day.
