How can I sensitively tell my girlfriend that her armpit hair affects my attraction during intimacy?

I’ve [27 M] been dating an amazing woman [27 F] for two months, and we’ve recently committed to each other. Our relationship is strong; we communicate well and resolve disagreements effectively.

Recently, she hasn’t shaved her underarms for about a month. While body hair doesn’t generally concern me, I’ve noticed that during intimacy, her underarm hair diminishes my attraction in the moment. I feel guilty for feeling this way, as it seems superficial. I personally keep my body groomed because I find excessive hair uncomfortable. Even if I didn’t, I would be open to her preferences if she communicated them to me. For instance, she suggested I grow my head hair longer when we first met, and I was receptive to her input.

How should I navigate this situation?