Your mother will be thrilled by your gesture no matter the outcome. Just remember that your music is a unique present and not a performance for pay or a competition for a prize.
I have fewer problems when I can concentrate on the sharing aspect. Some of my best playing happens in nursing homes, story times for children and other situations where music is woven naturally into the fabric of the events of the day. I do not seem to feel the same pressure that I feel in more formal settings, i.e. Recitals, Open Play at Guitar Society where the chairs are set up in rows (except for the victim's, oops the performer's) and it feels like I am facing a firing squad.
I suggest doing what you can to control the setting to keep things as informal as possible with the primary focus on the guest of honor. Good Luck and May you make some happy memories together!