For a beginner that's not to bad going. Remember the abdominals are like any other muscle group & also need proper rest. I only do weighted cable crunches once a week.
Not seeing any shoulder movements so would advise a type of shoulder press. Are you able to squat? There is no better movement to not only hit your entire legs but also your core. Even if you start at a relatively light weight to get the form right. This is much better than isolation machines.
Don't neglect pushups on a chest day as a movement either.
I'm only 5ft 10" & my height has never been an issue