I agree that either of these would be ideal for a first punt. If you go ahead it would be a good idea to mention during the booking process that it is your first time. I'm sure Bex or Sarah will both be accommodating to helping a newbie.
One other thing. We, obviously, have no idea of your circumstances and why you wish to have a punt, but please be aware you will be taking a step which cannot be reversed, so think carefully about any potential post-punt remorse or guilt. Also, this 'hobby' is very addictive, expensive and, at times, nerve racking. Definitely not for the faint hearted!
Good luck!