New rider needs help

I just learned how to get up on my board this year. I have got that part down good but was wondering about something I ride a CWB Sol finless but when I try and start to edge out the board fills like it wants to slide out from under me is this because of the fins not being on or do I need to lean in to it harder I ride at 65ft about 28 30 mph is my speed and rope distance ok or do I need to shorten the rope and speed up. I meant to say the board has 2 molded fins on each side also. Thanks for any help in advance also if anyone in the Memphis, tn. area wants to go out during the week in the afternoon let me know I am looking for a 2nd and a 3rd to get some more riding in.