Welcome to club lupo
sounds like everything is ok. Just top up the coolant with a bit of water and it'll be fine.
but engines don't like being started from cold and run every now and then (just idling without being driven). The trick is to take the car for a good half hour drive till it gets properly warmed up, then park it with a hot engine and leave it for up to six months. Ideally with the battery disconnected. The condensation (combustion products) in the exhaust affects all the internal components.