When is the right time to kiss a girl during a movie?

I just graduated HS and I was really down over a breakup, like I could never stop thinking about it and sometimes when I was just laying down at night I cried. I went out a few times with friends, and a lot of issues were going on between my mom and I so I had just moved in with my dad, but I was getting depressed. On my 18th birthday my ex hand actually wished me happy birthday (first time talking since the break up) and I felt somewhat better. Also my friends had a surprised dinner for me so I felt a little better with that too. That night my bestfriend took me to this party and I had a great time. This really hot girl who I had seen around school (she's a rising senior this year) was there, I had never talked to her before, mostly because I was afraid to, or I'd be in a relationship. But that night we ended up dancing and she grinded on me and we ended up making out and almost hooked up. Her parents were calling her so I ended up taking her home and she put her number in my phone. Well 2 weeks later (this week) we ended up going on a double date with my bestfriend, his gf, and this girl (who is my bestfriend's gf's bestfriend). We went movie hopping and we ended up making out but I never knew when the right time was. I had my arm around her and she had my hand. Sometimes she'd get extra close and grab my hand a little tighter and I wasn't sure if that was a queue for me to kiss her or not... Because a few seconds later she'd not hold me as tight and not have herself as close.