Is it normal that i still relive my gay college experience?

Relive as in reminisce fondly? Or relive as in it just keeps popping up as a simple memory? If you're fondly missing it, it may be a sign you're not straight. If it's just a random memory that's sticking around, it could mean that or it could mean nothing.

Sounds like your questioning your sexuality and realizing you are either hetroflexible or bisexual

It could mean one or two things, one your gay and you reminisce about it fondly, or two, its hard to forget it because its such a uniquely weird experience. I mean it stands out, that is , if your straight.

I'm also in my 70's but did not have anal sex (receine) until I was in my 30's. At that point I became bi and have lived (and still do) that life since so still making new memories.

Normal to remember your gay experiences, what you're describing sounds really really normal in my opinion, it is also normal to remember them as they are part of you and mostly because its your old memory.