I see you're new to bitcointalk, welcome! Just an FYI, asking questions like this are usually pointless. No one here can predict the future. If you are looking to buy and hold until 2018, then I'd say just buy now, hold the coin in a wallet, and don't look at the ticker every day. It's bound to go up in the current state of the market, but I cannot speak on behalf of the 2018 markets - especially Q4 2018, who knows what the market will be like at that point in time.

As of now, IOTA is in the top 10 for marketcap. That usually leads to good things. Ripple has 38,739,144,847 XRP in circulating supply - 19x more than IOTA. At the time of posting this comment, ripple is ~75-77cents. If XRP had the same amount of coins as IOTA (2,779,530,283), then it's current cost would be 14 dollars. Just some food for thought. Once IOTA hits a market like Bittrex, I'm sure marketcap will grow, hoping for 10 dollars+ one of these days.