I've been using a 150 as a starting out board for the last couple of years. It is definitely soft enough to use in the park but you may find in a season or two, as i have, that you'll want something a bit stiffer and more stable at speed. Having said that i'm progressing towards freeride more so than park.
If you're improving relatively quickly then a skate banana which is a little bit stiffer otherwise a very similar board may serve you for longer as you get more confidence at speed.
Any banana will be pretty catch free and easy to learn on, the softer flex of the carbon credit will be a little more forgiving for you as you're learning.
I was very happy to have been talked into the carbon credit and in a couple of years time you may want a new deck anyway because you will really start to know what you like and the CC is the cheaper option.
I think a 153 would be about right for you.