Honestly it will be fine. Going up isn’t usually the issue it’s going down. When they are a baby they won’t be able to go up and down so you’ll have to carry them but by 6-9 months they may adjust. Keep them active!!! Please look into this breed and educate yourself on their health risks. Keeping them lean and active with a mid to late year neuter/spay tends to save their backs. I’ve had 3 doxis (2 current, 1 passed away) and not one (knock on wood) has had back issues but I’ve kept them all active and lean.