I don't know how well 'speed' on an indoor trainer translates to speed in the real world, so like Toadmeister says, I wouldn't be concerned about it. Get out in the air, enjoy the sights, sounds and smells. Wear yourself out a few times and then be surprised a couple weeks later when you're going faster without getting as tired.
For me, one of the great things about riding where I live is that no matter how young or old, fat or thin, slow or fast you are, there's always someone who's more so. A lot of the time, I get to be other people's "older, fatter, slower" rider, but sometimes I get to be somebody's "older, fatter, faster" rider, which is gratifying.
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"Don't take life so serious-it ain't nohow permanent."
"Everybody's gotta be somewhere." - Eccles