Yes, perfecly fine if you not too tired or nauseous go for it. Ive asked my nurse same question and she said its fine throughout the entire pregnancy. Just dont do anything silly to put u at risk of yeast infection and so on... eg like no anal to front to carry germs ....
And some good news on this topic if youve wondered... im week 15 now and want almost everyday (poor hubby). Also the higher hormone levels leads to much better orgasms... ( coming from someone who struggles to get them)
Enjoy.