You knoe ukemi very well already. And that's a huge plus when starting Aikido. Also SOME techniques are similar. I mean both developed from jujitsu. My father (a practioner as well) once said that Aikido and Judo are somewhat brothers - like Earth and Venus are sisters:P So when great Master Kano formed Judo he took some things from jujitsu and dropped other things, O'Sensei Ueshiba dropped the things which were taken into judo and took the things what weren't in there. The only minus which could be is that you are going to have a little more hard time on learning the stances and the footwork, also using even more opponents power (as for example in koshinage, the hipthrow which is in judo as well but the essence of the throw is different
And you have know already how your body works (huge plus) you know how to attack and grab (huge plus) so happening to know judo before taking up aikido is definitely an advatnage not a disadvatnage.