If you have DVX Standard then no problem at all when you upgrade to DVX Professional as it is the same tool, using the same way to store TM! You simply open the projects, the same way you did with the Standard version (The Standard edition is a thinned out edition lacking a lot of functionality, i.e. does not allow project creation and export, plus many other things, see here for a comparison of different DVX editions
Even if you switched to another tool, you could still export DVX TMs as tmx files and import them into the other tool.
I am absolute beginner with CAT tools. Studied some of the tools in Translatorstraining and now I am working in a trial version of DVX Standard. I downloaded two of the manuals that I found on the official website. But I start wondering whether it will be better to try Professional version? Do you think it will be better and will I be able to transfer the Translation memory (though it is not big) I already have to the other version of the product. I have about 20 days to decide.
P.S. Happy New Year! Wish you all the best!