You can but you'll need a permission note from your mom. Seriously it's not a big deal, you can use both at the same time, nothing says you have to quit cold turkey. It would be more beneficial though i think to link discussions to the Fediverse rather than just to Reddit.
Instead of just tweeting, toot to the Fediverse as well. Try not to be annoying about it demanding people use the Fediverse, just do it the quiet sneaky way. Get people clicking Fediverse links with topics they would be interested in, and with their own volition they will learn about the Fediverse and come to look at it as a viable choice, hopefully.