I'm attending a wedding with my girlfriend; what should I do?

I am seeking advice from those with more life experience.
I am attending the wedding of an older acquaintance whom I haven't been close with for about 5 or 6 years.
My girlfriend, who has never met him, is coming with me.
I originally planned to give 200,000 KRW, but since my girlfriend is coming, I was planning to give 300,000 KRW.
However, my girlfriend said she wants to contribute 50,000 KRW herself.
It feels awkward to give 350,000 KRW, and it also feels awkward to give 400,000 KRW by adding her 50,000 KRW to mine.
It's also awkward to give separately as two individuals.
What would be the best way to handle this situation?