No. If you declined professionally, it is reasonable to reconnect when your circumstances have changed.

Reference the earlier exchange briefly, explain that you are now actively exploring the firm and ask whether they would still be open to a short conversation.

Do not pretend the earlier message never happened, but you also do not need a long apology.

If they do not respond, move on. The goal is to reopen a genuine connection, not create an obligation. For more on reconnecting and handling the conversation naturally, see the consulting coffee chat guide and the experienced-hire networking guide.

I did this after about six months and the person was totally normal about it.