Is it bad to ask someone out if they haven't initiated contact

No contact from her in the first few days does not mean she is not interested. She might not have seen your message yet. She might have seen it but is still deciding. Or she is busy and hasn't gotten around to replying.

Matching, following, or accepting a request already signals some level of interest. She chose to let you into her messages. That baseline exists whether or not she's typed anything back yet. People often sit on matches for a week before engaging. Some are on apps multiple times daily. Others check once a weekend. Read the platform context too: Snapchat conversations move faster than email. Hinge comments can take longer to reply to because they feel more formal.

If you've sent one solid message and it's been less than three days, silence is not a problem. If it's been a week and nothing, her interest is probably elsewhere, but that's different from the situation you're facing.

Your opening message needs to do two things. Show that you actually looked at her profile and give her a reason to type something back. This means no copy-paste openers and no questions she can answer in one word.

If her profile mentions hiking, don't say 'I like hiking too.' Say something that shows you noticed the specific thing she said about it, or ask her a question that requires her to think. 'Which trail near you would you recommend if I had a whole Saturday?' is better than 'Do you hike often?'

The goal is not to seal the deal in one message. The goal is to show enough self-awareness that she wants to keep the thread going. That's what actually hooks someone in. After she replies once, then you can think about asking her out.

Send your message and then do not send anything else for at least three days, even if you don't hear back. One message is a gesture. Two messages start looking like you need the validation. Three looks like you are not paying attention to whether she's engaging.

If she replies, have one or two back and forths before suggesting a specific plan. This gives her time to see that you are not a bot and that she actually wants to meet you. If she never replies, accept it and move on. One unanswered message does not warrant a follow-up.

If she does reply but stops after a few exchanges, do not ask her out anyway. She's already told you she lost interest by going quiet mid-conversation. Asking her out at that point just adds another unanswered message to the thread.