Technically a second hand cot should work well with a brand new mattress. One factor to consider is whether the wear & tear will affect the durability of the cot in the long run. If you’re not particular about cots, there’s actually a lot of good conditions with no wear & tear cot going for free on Carousell. My mil bought the Raab cot for my baby…. And it has since become a storage bed since day 2. Baby only slept in the cot for a day and has been cosleeping with us as it’s easier to tend to her at night. (Currently 4.5months) So if let’s say you intend to let her cosleep, you might want to consider whether you want to get a new bed since it’s the first baby 🥰