If your laptop is made within the last 10 years plus you are probably running a 64 bit processor. I would recommend being clear about what processor you do have. If you do have a 64 bit processor run 64 bit Debian. As far 3GB of ram I have white macbook 2007 with 3gb of ram runs Debian 10.9 fine. It really matters what desktop environment you run. I would recommend Xfce or Mate because they use less ram to run or just a windows manager like awesome if you want to go really light on ram usage. For ease of installation I would recommend a debian plus non-free iso with your desired desktop environment. Also running a 64 bit iso helps you extend/future proof your laptop because 32 bit support will be phased out at some point in the future. Good luck.