kayveraa's journey

I have two interviews lined up for tomorrow for entry-level positions as a medical/front-desk receptionist. If I get an offer, this would be my first job, which is exciting! However, I have two prior commitments in August that were planned months ago, from the 13th to the 16th and from the 27th to the 29th. I'm unsure whether I should bring this up during the interviews. I’m leaning towards waiting until I receive an offer before mentioning it, especially when they ask about my preferred start date. Any advice on how to handle this?