Personally, I would be honest with your girlfriend and let her know what's going on. When you start making all kinds of excuses that is when you get caught up in a tangled web. Who needs it?....it causes too many headaches. Thus, this particular situation should help you get things straightened out in your mind for future commitments....a lesson to learn???
Before you do anything, really decide for yourself what you want - and if you take one over the other, will you be happy? Will you have fun? Will it be worth it? But, as I stated, honesty is important - it's the best policy!
Don't force yourself to do something just because you said so even though following through on a commitment may be considered proper....(although one's word should be their bond).....however, if you don't feel comfortable in doing something, particularly concerning this situation, it won't do anybody any good - and may cause problems and/or bad feelings. Let this serve as a lesson - should you make a future commitment, not to back out, regardless - thus, give it good thought beforehand - it's nothing to be ashamed of - for we all live and learn every day.
With regards XXXXX XXXXX uncle, please know that my prayers and thoughts are with him - and you!
Please take care.
Peace, Love & Happiness,
The Mystic Wave