今天我继续经历我的种种“第一次”。

今天，我又经历了很多第一次。 or 今天，我又体验了很多第一次。

今天我经历了好多的第一次。（意思是：我做了好多以前从来没有做过的事情）

今天这些第一次经历继续了。Today all of these firsts keep happening. Literally, it means today all of these first experiences continued to happen for the second time, for the third time... So, it does not make any sense. maybe you want to say something like, 今天我又经历了好多新鲜事(好多第一次)。(in a casual manner) Today again, I've experienced many fresh things. 今天我的好多第一次没了。(in a playful tone) Today many of my firsts were gone. Today I've lost many of my firsts. 今天我又有了很多第一次的经历。(in a neutral way) Today I continue to experience many firsts.

我今天又遇到好多新鲜事儿。 "continue" indicates the continuation from yesterday's exprience? Then 又 fits well in the translation.