Brandon James Asplin, 21, pleaded guilty at Bendigo County Court on Thursday to two counts of sexual penetration of a child under 16 and failing to comply with sex offender reporting requirements.

The court heard the North Bendigo man met the girl, who he believed was 17, on an internet meeting site in early 2011 when he was 18.

When the pair met in person, she told Asplin she was only 15 and he broke up with her, before resuming the relationship a short time later.

One night in July 2011, at a Bendigo race track meet, Asplin took the girl to a secluded area near a children's playground and had sex with her.

In a statement to police, the girl said she had felt too young to have sex with him, but he had talked her into it.

In a victim impact statement read to the court, the girl said she had become fearful of new people, especially men, since the incident.

She said she had also experienced flashbacks and nightmares, had become unwell due to rapid weight loss and had self-harmed.

Defence barrister Russell Kelly told the court his client was "a bit of a loner" who was still in an adolescent stage of development.

Mr Kelly said psychological reports showed Asplin had mild features of autism spectrum disorder and had cognitive and social limitations.

He also submitted the two-year delay in his client being charged with the offences meant Asplin, now 21, could not be sentenced as a young offender.

Judge Paul Lacava criticised the delay as disgraceful, describing it as "almost a breach of duty of public office" and one which had placed the offender in a disadvantaged position before the court.

In sentencing, he noted Asplin's early guilty plea, his efforts to get his life in order since the offending, and his reasonably good prospects of rehabilitation.

Judge Lacava imposed a three-year community corrections order, requiring 200 hours of community work and a string of mental health, personal development and sex offender programs.

He also ordered Asplin report as a registered sex offender for life.

The maximum penalty for sexual penetration of a child under 16 is 10 years imprisonment.