It really feels to me like you’re her backup boyfriend. If she can’t have her ex, maybe you’ll do.

If you were the one she wanted, she’d be ready for the relationship now. Her saying “down the road” seems to be code for “once I’m sure I can’t get my ex back and he’s moved on”.

You deserve to be the star of the relationship and not a backup dancer. Let her go explore her feelings and you go find someone who wants to be your one and only.