I am a beginner in Japanese who is not even done learning katakana yet, so forgive me if this is a noob question. I know that when っ comes before a character, say the word was まって, there would be a pause before the て. (Correct me if I'm wrong.) But I've read a few things that just start with っ and then normal characters, so I'm wondering what it means/how to pronounce it. Also if you couldn't tell because there is nothing to compare to, it is the little tsu, not the normal one.
Some languages, like Korean, have so-called "tense consonants" that can start a word. These are romanized as starting with a geminate (doubled) consonant, such as 까 (kka). Japanese has a similar kind of phenomenon with geminate (doubled) consonants that appear mid-word, where the geminate is indicated by a small tsu, っ instead of the full-sized つ.
Japanese doesn't have tense consonants at the start of words as a feature of the language, which is why it may be hard to find information about this. It's also why some folks might be confused by your question, and ask for more context.
However, although rare, it is possible that informal texts (such as manga in particular) might indicate a word-initial tense consonant to try to illustrate how someone might be speaking, perhaps in surprise, or as a sound effect.
For how to pronounce it, it's hard to explain at the start of a word because English doesn't have tense consonants either. "Tense" is a good rough idea: try saying the consonant with your breathing more tensed up before releasing the consonant. Imagine what it might be like to say a word like "cat" normally, and then imagine what it might sound like to say "ccat" with an emphasized
/k/ sound -- a close approximation could be how people with a stutter say words that are difficult for them to pronounce, where the breath catches before finally releasing.
If the above doesn't fully address your question, please comment and I will edit my post accordingly.