Question: Do you think it's a bad idea (or it doesn't really matter) to buy a house from the same realtor that is selling it? We've found something we're very interested in.
Answer: Both realtors are paid by the seller, so you can't really expect either to represent you well as a buyer. It is important you be aware of how real estate works so you can tell your realtor what you want. If you want to get a realtor to represent you, find a good one and offer to pay them for finding a house. Offer to pay them for their work, even if they don't find you the house you want. This really changes the relationship so you can demand and get the things you want.
Have you ever heard your realtor say, "I can't take that offer to the sellers; they'll laugh at me"? In that situation it's obvious they're working for the seller, not you.