By all accounts GA are excellent live.
Yes it will be glitzy with lots of dancers, but they do sing, they have a crop of pop-tastic songs, and I think they will be a great night out.
If people are teasing you, take lot of no notice - I have been teased about my musical tastes all my life, and I couldn;t care less. As a music writer I meet and interview the great and the good, but I have a (totally UN-secret!) passion for Euro-pop - 'Saturday Night' is one of my all-time fave records. I had tickets to see Abba in 1979 when their 'cool' quotient would be a few stops below Westlife in today's markings. Did I care? And i have been somewhat vindicated in the intervening years.
Love what you love, and don't give a toss if people put you down for it. It's music - the food of love. Enjoy it!