Living in a semi - is it noisy?

We are 70 and have never lived in a semi, but are thinking of downsizing and in our area its probably the only option. I am worried about neighbour noise through the walls. I am a horrendously light sleeper. What are your experiences? We lived in a flat when we first married which was pretty noisy, then a mid-terrace where we also had noise, but after that its been detached houses and bungalows. Will I be able to hear people next door in a semi? and are older houses better or worse from this point of view?