For your uses, the 18-55mm is the more important lens to start with. It covers wide-angle to short telephoto, which is much better for indoor family photos, travel, and general everyday shooting. The 55-250mm is useful for sports, wildlife, and other distant subjects, but it’s too long for most indoor situations.

If you want the most flexibility, get both: use the 18-55mm for general and indoor photos, and the 55-250mm when you need reach outdoors.

If you’d rather avoid changing lenses often, an 18-135mm style zoom can be a simpler beginner-friendly option. It gives you more range than the 18-55mm and reduces lens swapping, which is more convenient and can help limit dust getting into the camera during changes.

So: start with the 18-55mm for family/vacation photography, add the 55-250mm if you expect to shoot sports or distant subjects regularly, or consider an 18-135mm as a one-lens compromise.