I've traveled alone before but within the country. It was my first experience too. I still choose to fly to get to the destination (from Ontario to Quebec, Canada). So I did all of what you're about to do, alone as well. It was a 1 month french immersion camp that I undertook back in high school (11 years ago 😬, damn I'm old (28)). My stutter was worse then than it is now but I don't remember it being a nerve racking experience. Actually I enjoyed it more than when going with other people because of the independence and it was just a brand new experience. I understand that it's a bit different for you because you're going to a foreign country. There may be a language barrier and the cultural norms will be different. But remember you can develop back up plans. I just got back from the Dominican Republic and wherever I'd go up to talk someone I'd pre-type what I wanted to say in the google translate app on my phone (remember to download offline languages). Then when I'd walk up to them to speak, I'd first try saying it in English (not even going to try speaking Spanish, cause I block way more in it), then I'd show them the app translation. I'd hand them the phone with the google translate app open (remember to switch the languages for them), so they can type in their response.