If you want only one image if the stairway, you need to increase the block size. To increase the size of the cats, I would use a copy machine to increase the pattern size.
I tend to agree with Pat - use this pattern as is... and choose something different for your first large quilt.
I must admit, what you have chosen would teach you a lot of different things. There are piecing and applique included. It would be a real challenge. Do you have a local quilt shop where there might be someone to ask questions and be shown the answer (as opposed to reading an answer here)? We do love to help, but sometimes it is easier to learn by seeing...