Would Christians mind if a non-believer sat quietly in church during Sunday service?

Hey guys, I’m a 21F ex-Muslim and currently agnostic. A couple of days ago I was on my way to a business meeting when I passed by a church. I heard people singing inside and it really touched me I genuinely wanted to stay and listen but I couldn’t because I was already running late. It was Sunday around 11 a.m. When I finished the meeting (around 2 p.m.), I passed by again but I think the singing had stopped. I didn’t get a chance to ask anyone since I wasn’t alone. Now I’m thinking of visiting the church again next Sunday, but I’m not sure if I’m allowed to go in and just sit quietly to listen. I’m not Christian, and I don’t want to make anyone uncomfortable. I just felt so peaceful when I heard them, even from outside. So my questions are: – Would it be okay if I went inside and just sat to listen during the service? – And what exactly were they doing at that time was it a service a special event or just prayer time?

Thanks in advance for any answers!