>My boyfriend and I are both generally anxious people who overthink way too much.

It's good that you are aware of this. I think it's important to pay attention, and learn to notice when the anxiety starts kicking in -- the same would be wise for him to do.

I see absolutely nothing in your story that counts as a red flag. You're both relatively young and in uncharted territory. It sounds like your boyfriend is being honest and open about his fears, which are clearly causing him to spiral a bit.

This is something to continue exploring together. Having regular conversations about your relationship and how you are both feeling is part of the recipe for creating a strong foundation so that your boyfriend's fears do not come true. It's really a good thing he spoke about them, as you guys can now work on it together.

The fact of it is, the longer a relationship goes, the most likely it is you will encounter hardships together. That doesn't mean any less love, but there will be ebbs and flows of intensity. Life will get in the way, and you might drift a bit, but if you stay committed and keep communication open and effective you'll always be able to bring it back.

If you have access to it, couples counseling could be a good idea to explore. It's not just for people who are already having problems; it can be a good place to explore and learn better communication and get some stuff out in the open.

>Of course, me being the overthinker that I am I am wondering in the back of my mind if I should put my guard up a bit, pull back a bit, be skeptical of whether or not he truly has doubts about this.

Unless there is more to this story that you haven't shared here, or he's violated your trust or hurt you in other ways, this is the one thing you should definitely not do. Putting up this wall is a small act that could snowball into a bigger rupture. It's a little acorn of mistrust that prevents deeper connecting, and could cause future actions of his to be seen in a more negative light.