Make one now, even if you are just getting started. You can list the topics you would like to speak about, and then add your talks as you schedule and give them.
Here are 3 places you can host your speaking profile.
Most blogging platforms e.g. wordpress, blogger allows you to add pages independent of the blog posts. You can add a speaking page there.
Example: Annyce Davis.
If you don’t have a blog, you can use GitHub pages to host your speaking page.
Example: Margaret Maynard-Reid.
If you don’t want to deal with formatting your page, you can create a profile on lanyrd.com. You will need to find the conference you are speaking at (create it if there is no entry), add a session, and mark yourself as the speaker. It is a bit of a hassle to enter all that structured data, but you get cool stats.
Example: Estelle Weyl.
Even more examples: https://github.com/asg-feminati/speakers
Watch my How to Write a Conference Proposal talk where I mentioned how to use speaking profiles to discover conferences.