Depending on how she felt talking with you for over an hour it might be too late. You want to escalate it sooner rather than later so you don't get friend zoned. Don't become that person she goes to to talk to about all her issues or whatever. Make it clear you want to do more than just go on walks. Don't do lunch dates or anything like that, do dinner dates or go out for drinks. Friends meet up for lunch, dates should be at night. And if she does reject you, stay friends and move on to the next girl. Don't get hung up on it and learn from the experience.