My ex has been in touch at the worst possible time!

I used to date this girl a long long time ago. We were very young back then (17 and 18). We only dated for a year. I’d say we were each others first love. She lost her virginity to me. It was a special relationship all round. Despite all that, I was a moron. With being 18, I had been new to the scene of clubbing and realising there were other girls in the world. I ended up kissing another girl on a night out and my girlfriend found out through a friend. It was awful at the time. Obviously we broke up. A few years later we tried to re-connect. We’d meet up and what not but evidently it just didn’t work out. It has now been 11 years since we last spoke or saw each other. We’ve both had new relationships, i’ve had 4 partners since, I’ve travelled, etc.
For some reason, this girl has always popped into my head from time to time over the years. We’ve always followed each other on social media platforms, always liked posts/stories on Instagram, more so in the last couple of years. I remember always saying to my mum, if one girl could turn my head, it would be her. I’ve always had a soft spot for her despite us being together young (we’re now both in our 30’s).
About a month ago, she sent me a message completely out of the blue because she had found something that I gave to her when we were together. It had been kept all these years. It got us talking and we had so much to catch up on. We even met up for lunch, it was amazing.
Here now lies the problem though. I am leaving the country to work abroad for what could be a couple of years. I’m terrified in case this is an opportunity to reconnect, now we’re both older, more mature, it could be right.
Do I tell her I still have these feelings? Do I cut my trip short? Cancel it altogether if the feelings are mutual? Do I ask her how she feels? I’d never ask her to wait as I feel like that’s selfish and I know she’d never ask me to stay.
Do we ride our luck and hope the universe puts us on the same path again somewhere down the line? If it’s truly meant to be?

The last thing I want to do is put any pressure on her. If this is it, it needs to be right. I need to get this right.

Any advice for a confused guy who has been in love with the same girl for nearly 15 years?