The marriage and other details of your child can be better analysed with your child's chart with the child's birth details and not your chart.
As per your chart's Saptamsha for children, on a generic level, the current ongoing time is the right time for the marriage and this period lasts up to mid 2025.
You may like to get the chart of your child analysed.
Best Wishes.
Seventh lord of Saptamsha is Mars posited in debilitation and posited in the tenth house in Saptamsha conjunct Sun; Jupiter Maha Dasha ongoing with Mars Antar Dasha currently followed by Rahu Antar Dasha till mid 2025.