My wife new a girl in high school who left her locks in a ponytail all day every day. She even slept with them in a ponytail. Eventually she had to cut them into section because they matured into 1 giant lock.
It's much better for them to hang loose as much as possible. Tying them up will slow the process down
its absolutely better down the more u put em up the slower it will gio but also the more the roots will trey to form a single ponydread