Love is supposed to change you, and it will. This is how we determine the quality of a relationship: by the person we become when we're in it. People always say the opposite – that you should never change for someone else – but with the right person, you will evolve rapidly. The right person will show you the very best parts of you, and you'll want to be your best self for them.
This is the kind of love worth choosing, worth sacrificing for: not that which accepts unconditionally, but which sees the best in you, and inspires you to be more, and more, and more. This is the kind of love you want to last a lifetime. The kind that you will get to the end of your days and think: I would be a fraction of the person I am had I not been with them.