Congrats Lucinda. There just isnt any comparison between a choper grinder and a burr.
If you are getting 60 mls in approx 30 seconds, and the portafilter locks on readily....and the coffee tastes good, there should be no problem with the grind setting.
Can you tell there is channelling? It may be the puck broken up after extraction, parts of it sticking to the shower screen. If it is decidely wet, soppy looking, you need to increase your dose.
Try weighing the loaded basket, aiming for between 14 and 20 grams.