I know that this was a low-end machine, but I'm actually surprised that 64-bit hardware (and I can't find a version of this machine that isn't) shipped with a 32-bit version of Windows (and it would have been earlier than Windows 10 given the introduction was well before Windows 10 appeared on the scene).
You've been given good advice. So long as you take a complete system image, and a separate backup of all your user data files (as this is what you'd copy those back from), and take a good inventory of the programs you have installed and will need to reinstall it is not difficult to upgrade to Win10 64-bit.
Unless they've changed things with the Media Creation Tool be certain that you select the 64-bit version. The Media Creation Tool tries to determine whether it should download the 32-bit version versus 64-bit version and there's also a version you can burn to a bigger-than-4GB USB that includes both 32 and 64-bit. However, I don't know whether it makes this determination based on hardware specs it finds or the current version of Windows it finds. You'll definitely want to use the "Create installation media for a different machine" option so you can be certain to get the 64-bit version of Windows 10.
The HowToGeek article referenced by dc3 is excellent. The only nit I'd have to pick with it, and it is a nit, is that if you took a full system image of your system with 32-bit Win10 running on it prior to upgrading to Win10 64-bit, and wanted to revert, you could just use that system image to recover from. It would save a lot of work with having to reinstall programs, drivers, etc., from scratch.
Edited by britechguy, 23 April 2017 - 10:24 AM.
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1809, Build 17763
Presenting the willfully ignorant with facts is the very definition of casting pearls before swine.
~ Brian Vogel