Water height just over 60 cm

We have built the pool yesterday and the kids (6 + 12) no longer want to get out. I bought the Aldi set for 100 Euro incl. Pump and ladder. Construction was Ok, filling took about 7 hours. The lawn should really be flat, otherwise the pool depends and he can not be filled. We have about 5 cm difference in height and the water in the pool is unfortunately only 60 cm deep.