1. What they believe a committed relationship looks like, their goals and aspirations in life, if they want to be in a committed relationship with you.
Something like, “I want to take our relationship to the next level, what do you imagine a committed relationship looks like?”
2. If you aren’t sexually active with each other yet, it would be good to know her plans in that area. If she’s waiting for marriage you best know that now.
In general in regards to future plans – remember that’s not a contract, that’s a good general bit of background about what she’d like in the future. People change – especially if you are young.
Also – you might be overthinking this. You aren’t committing to a lifetime together. Presumably you are talking about committing to seeing each other exclusively, so you don’t need to be on the same page with everything future-wise.
The biggest question you should ask yourself is: Do I like this person enough to stop seeing other people, do I want to get to know her better, and do I trust her enough to open up and let her know me better? You can learn all that other future stuff on the way – this isn’t a job interview for her.