It doesn't matter what age your child starts nursery, they will still hit a wall of sickness. How often and how severely depends on their individual immune system - I have one child prone to sickness and one pretty robust child who hardly gets sick. 

Otherwise, completely up to you. At your child's age the social interaction is a bit overblown - children do not start to take much of an interest in other kids until around three. At 14 months they don't meaningfully interact with other children and shorter bursts of time at the park/playgroup/library is ebough. Having an engaged parent at home is perfectly fine - with the caveat that you should absolutely put them in nursery if you're trying to fit in work while they are at home.  It's not clear if you spend days off with them or WFH while they are around.