Congratulations to your DD! Such an exciting adventure. My only advice, since almost everything has been said, is just take it day by day....my DD was invited to pre-team last summer and after about 5 months we needed to take a step back. She wasn't having fun anymore, she started at 4.5 and had just turned 5 when we went back to rec. I honestly thought we might take a session off, but now my DD loves it more than ever.
Follow your DD's lead, if she loves it, who cares what people say? Coaches don't invite kids if they don't think they have the ability to do the hours. Honestly, you will know if it is too much.